Deprecate the HorovodStrategy

[carmocca]

What does this PR do?

Closes #12065
Closes #10863
Closes #13665
Closes #11975

Does your PR introduce any breaking changes? If yes, please list them.

None

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Make sure you had fun coding 🙃

cc @Borda @tchaton @awaelchli

[github-actions]

⚡ Required checks status: All passing 🟢

Groups summary

🟢 pytorch_lightning: Tests workflow

Check ID	Status
pl-cpu (macOS-11, pytorch, 3.8, 1.11)	success	✅
pl-cpu (macOS-11, pytorch, 3.9, 1.12)	success	✅
pl-cpu (macOS-11, pytorch, 3.10, 1.13)	success	✅
pl-cpu (macOS-11, pytorch, 3.8, 1.10, oldest)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.8, 1.10)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.9, 1.11)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.10, 1.12)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.10, 1.13)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.7, 1.10, oldest)	success	✅
pl-cpu (windows-2022, pytorch, 3.9, 1.11)	success	✅
pl-cpu (windows-2022, pytorch, 3.10, 1.12)	success	✅
pl-cpu (windows-2022, pytorch, 3.10, 1.13)	success	✅
pl-cpu (windows-2022, pytorch, 3.7, 1.10, oldest)	success	✅
pl-cpu (slow, macOS-11, pytorch, 3.7, 1.11)	success	✅
pl-cpu (slow, ubuntu-20.04, pytorch, 3.7, 1.11)	success	✅
pl-cpu (slow, windows-2022, pytorch, 3.7, 1.11)	success	✅
pl-cpu (macOS-11, lightning, 3.8, 1.13)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.8, 1.13)	success	✅
pl-cpu (windows-2022, lightning, 3.8, 1.13)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py, tests/tests_pytorch/conftest.py, tests/tests_pytorch/deprecated_api/test_remove_1-10.py, tests/tests_pytorch/helpers/runif.py, tests/tests_pytorch/models/data/horovod/train_default_model.py, tests/tests_pytorch/models/test_horovod.py, tests/tests_pytorch/utilities/test_imports.py.

🟢 pytorch_lightning: Azure GPU

Check ID	Status
pytorch-lightning (GPUs)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py, tests/tests_pytorch/conftest.py, tests/tests_pytorch/deprecated_api/test_remove_1-10.py, tests/tests_pytorch/helpers/runif.py, tests/tests_pytorch/models/data/horovod/train_default_model.py, tests/tests_pytorch/models/test_horovod.py, tests/tests_pytorch/utilities/test_imports.py.

🟢 pytorch_lightning: Azure HPU

Check ID	Status
pytorch-lightning (HPUs)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py, tests/tests_pytorch/conftest.py, tests/tests_pytorch/deprecated_api/test_remove_1-10.py, tests/tests_pytorch/helpers/runif.py, tests/tests_pytorch/models/data/horovod/train_default_model.py, tests/tests_pytorch/models/test_horovod.py, tests/tests_pytorch/utilities/test_imports.py.

🟢 pytorch_lightning: Azure IPU

Check ID	Status
pytorch-lightning (IPUs)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py, tests/tests_pytorch/conftest.py, tests/tests_pytorch/deprecated_api/test_remove_1-10.py, tests/tests_pytorch/helpers/runif.py, tests/tests_pytorch/models/data/horovod/train_default_model.py, tests/tests_pytorch/models/test_horovod.py, tests/tests_pytorch/utilities/test_imports.py.

🟢 pytorch_lightning: Docs

Check ID	Status
make-doctest (pytorch)	success	✅
make-html (pytorch)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py, docs/source-pytorch/accelerators/gpu_faq.rst, docs/source-pytorch/accelerators/gpu_intermediate.rst, docs/source-pytorch/api_references.rst, docs/source-pytorch/common/trainer.rst, docs/source-pytorch/extensions/strategy.rst, docs/source-pytorch/starter/lightning_lite.rst.

🟢 lightning_lite: CPU workflow

Check ID	Status
lite-cpu (macOS-11, lite, 3.8, 1.11)	success	✅
lite-cpu (macOS-11, lite, 3.9, 1.12)	success	✅
lite-cpu (macOS-11, lite, 3.10, 1.13)	success	✅
lite-cpu (macOS-11, lite, 3.7, 1.10, oldest)	success	✅
lite-cpu (ubuntu-20.04, lite, 3.8, 1.10)	success	✅
lite-cpu (ubuntu-20.04, lite, 3.9, 1.11)	success	✅
lite-cpu (ubuntu-20.04, lite, 3.10, 1.12)	success	✅
lite-cpu (ubuntu-20.04, lite, 3.10, 1.13)	success	✅
lite-cpu (ubuntu-20.04, lite, 3.7, 1.10, oldest)	success	✅
lite-cpu (windows-2022, lite, 3.9, 1.11)	success	✅
lite-cpu (windows-2022, lite, 3.10, 1.12)	success	✅
lite-cpu (windows-2022, lite, 3.10, 1.13)	success	✅
lite-cpu (windows-2022, lite, 3.7, 1.10, oldest)	success	✅
lite-cpu (macOS-11, lightning, 3.8, 1.13)	success	✅
lite-cpu (ubuntu-20.04, lightning, 3.8, 1.13)	success	✅
lite-cpu (windows-2022, lightning, 3.8, 1.13)	success	✅

These checks are required after the changes to tests/tests_lite/conftest.py.

🟢 lightning_lite: Azure GPU

Check ID	Status
lightning-lite (GPUs)	success	✅

These checks are required after the changes to tests/tests_lite/conftest.py.

🟢 mypy

Check ID	Status
mypy	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py.

🟢 install

Check ID	Status
install-pkg (ubuntu-22.04, app, 3.7)	success	✅
install-pkg (ubuntu-22.04, app, 3.10)	success	✅
install-pkg (ubuntu-22.04, lite, 3.7)	success	✅
install-pkg (ubuntu-22.04, lite, 3.10)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.7)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.10)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.7)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.10)	success	✅
install-pkg (ubuntu-22.04, notset, 3.7)	success	✅
install-pkg (ubuntu-22.04, notset, 3.10)	success	✅
install-pkg (macOS-12, app, 3.7)	success	✅
install-pkg (macOS-12, app, 3.10)	success	✅
install-pkg (macOS-12, lite, 3.7)	success	✅
install-pkg (macOS-12, lite, 3.10)	success	✅
install-pkg (macOS-12, pytorch, 3.7)	success	✅
install-pkg (macOS-12, pytorch, 3.10)	success	✅
install-pkg (macOS-12, lightning, 3.7)	success	✅
install-pkg (macOS-12, lightning, 3.10)	success	✅
install-pkg (macOS-12, notset, 3.7)	success	✅
install-pkg (macOS-12, notset, 3.10)	success	✅
install-pkg (windows-2022, app, 3.7)	success	✅
install-pkg (windows-2022, app, 3.10)	success	✅
install-pkg (windows-2022, lite, 3.7)	success	✅
install-pkg (windows-2022, lite, 3.10)	success	✅
install-pkg (windows-2022, pytorch, 3.7)	success	✅
install-pkg (windows-2022, pytorch, 3.10)	success	✅
install-pkg (windows-2022, lightning, 3.7)	success	✅
install-pkg (windows-2022, lightning, 3.10)	success	✅
install-pkg (windows-2022, notset, 3.7)	success	✅
install-pkg (windows-2022, notset, 3.10)	success	✅

These checks are required after the changes to src/pytorch_lightning/strategies/horovod.py, src/pytorch_lightning/trainer/connectors/accelerator_connector.py, src/pytorch_lightning/utilities/__init__.py, src/pytorch_lightning/utilities/imports.py.

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