Keras v3 Support

[calad0i]

A# Description

Add keras v3 specific object-based parser and some layer handlers (no h5 or json loading supported). The current keras parser doesn't work with v3 functional models in general. This PR depends on #1094 , and the test added relies on #1101 .

Type of change

• New feature (non-breaking change which adds functionality)

Tests

test/pytest/test_keras_v3_api.py

Test Configuration:

Requires keras>=3.0. Skips the whole module if this requirement is not sufficed.

Checklist

• I have read the guidelines for contributing.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have installed and run pre-commit on the files I edited or added.
• I have added tests that prove my fix is effective or that my feature works.

[calad0i]

This PR will be rebased after its prerequisites are merged to resolve the conflicts.