Bump minimum Python version to 3.11

[nyalldawson]

Resurrect #56499

This was previously blocked by the mac packaging stuck on a very old python version, but that's no longer a consideration thanks to @m-kuhn's great efforts!

[github-actions]

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[agiudiceandrea]

Maybe documentation_check fails because it installs Python 3.10:

  documentation_checks:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Set up Python 3.10
        uses: actions/setup-python@v5
        with:
          python-version: '3.10'

To fix it:

diff --git a/.github/workflows/code_layout.yml b/.github/workflows/code_layout.yml
index 57b97153188f..139e94d5c6ff 100644
--- a/.github/workflows/code_layout.yml
+++ b/.github/workflows/code_layout.yml
@@ -24,10 +24,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Set up Python 3.10
+      - name: Set up Python 3.12
         uses: actions/setup-python@v5
         with:
-          python-version: '3.10'
+          python-version: '3.12'
       - name: Install requirements
         run: |
           wget https://www.doxygen.nl/files/doxygen-${DOXYGEN_VERSION}.linux.bin.tar.gz