Added readme to the aot_mlp example

[xintin]

This pull request includes the following main changes:

1. Added assertions to the aot_mlp example.
2. Replaced print statements with loggers.
3. Added requirements.txt for the aot_mlp example.
4. Added a README.md file for the aot_mlp example.

[ScottTodd]

Thanks! Sorry this went unnoticed for a few days. Just a few lint checks to appease and then we can merge this.

[ScottTodd]

The pre-commit link checks found a few minor style issues in this file and the README: https://github.com/iree-org/iree-turbine/actions/runs/11811883913/job/33237529472?pr=266

Docs: https://github.com/iree-org/iree-turbine?tab=readme-ov-file#optional-pre-commits-and-developer-settings

If you could fix those, that would be great. A maintainer could also push those fixes for you.

[ScottTodd]

Might want to suggest https://github.com/iree-org/iree-turbine/tree/main?tab=readme-ov-file#install-pytorch-for-your-system for some users rather than the stock torch requirement, at least as a note in the README ahead of the pip install -r requirements.txt. Installing the CPU torch wheel is much faster than the default (that includes tons of CUDA deps).