XAI support for rmdet_inst_tiny

[GalyaZalesskaya]

Summary

• Supported XAI for rmdet_inst_tiny for PyTorch (OV task is handled on Model API side)
• Renamed MaskRCNNExplainAlgo -> InstSegExplainAlgo since this algo is used for both Mask RCNN and RMDET Inst models

How to test

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have added e2e tests for validation.
• I have added the description of my changes into CHANGELOG in my target branch (e.g., CHANGELOG in develop).​
• I have updated the documentation in my target branch accordingly (e.g., documentation in develop).
• I have linked related issues.

License

• I submit my code changes under the same Apache License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below).

# Copyright (C) 2024 Intel Corporation
# SPDX-License-Identifier: Apache-2.0