Add Cropping layers support

[HamzaEzzRa]

Description

This PR adds support for Keras' Cropping1D and Cropping2D layers with Vivado and Vitis backend in both io_parallel and io_stream modes.

The implementation is straightforward and follows a similar style to zero-padding implementations. I added tests for Vivado and Vitis backends.

I have yet to run this on a board, but implementation was successful targeting a ZCU102, using Vivado 2019.1. Although this type of layer has a fairly niche usage, I still found a use case for it, and it could benefit the community.

Linked Issue: #1308

Type of change

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

Tests

I added unit tests in test/pytest/test_cropping.py

Test Configuration:

• io_type: ["io_stream", "io_parallel"]
• backend: ["Vivado", "Vitis"]
• model_type: ["1d", "2d"]

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.

[HamzaEzzRa]

pre-commit.ci autofix

[JanFSchulte]

Test error are unrelated to this PR. Looks good to me.

[JanFSchulte]

@calad0i Do you think this needs to be included explicitly also in the keras v3 parser, or should we let the fallback take care of it?