Support for Python 3.12

[sei-secheverria]

Mostly addresses #569, to add support for Python 3.12 to MLTE. More specifically:

• Updated supported versions in package and documentation to Python 3.12
• Updated Scenarios Demo model to new Keras format, to be able to use newest Tensorflow that supports Python 3.12
• Updated all dependencies that could be updated, to ensure compatibility with 3.12, and to get newest updates
• Removed demo-mac group, special macos package no longer needed with Tensorflow 2.17+

Also some minor project packaging and setup improvements:

• Added mandatory requirement to use Poetry 2.0, to take advantage of its improvements (and specifically, to 2.0.1, which fixes some release bugs in 2.0)
• Updated pyproject.toml to use standard project section as much as possible, since it is now supported by Poetry
• Improved and fixed some errors in Python versions and badges reported when uploading package to PyPi
• Updated JSON schemas, apparently due to new items now used by pydantic
• Fixed some internal document link bugs
• Some formatting changes due to new rules in formatter dependency tools