Refactoring instance segmentation modules

[sungchul1]

Summary

This PR includes:

• [x] Remove mmdet and torchvision directory & Refactor duplicated functions

      <table>
      <tr>
      <td> before </td> <td> after </td>
      </tr>
      <tr>
      <td>
  
      ```shell
      src/otx/algo/instance_segmentation/
      ├── losses
      │   ├── accuracy.py
      │   ├── dice_loss.py
      │   └── __init__.py
      ├── maskrcnn.py
      ├── maskrcnn_tv.py
      ├── mmdet
      │   ├── __init__.py
      │   ├── models
      │   │   ├── backbones
      │   │   ├── __init__.py
      │   │   └── swin.py
      │   ├── base_roi_head.py
      │   ├── bbox_heads
      │   │   ├── bbox_head.py
      │   │   ├── convfc_bbox_head.py
      │   │   └── __init__.py
      │   ├── custom_roi_head.py
      │   ├── dense_heads
      │   │   ├── __init__.py
      │   │   ├── rpn_head.py
      │   │   ├── rtmdet_ins_head.py
      │   │   └── utils.py
      │   ├── detectors
      │   │   ├── base.py
      │   │   ├── __init__.py
      │   │   ├── mask_rcnn.py
      │   │   ├── rtmdet.py
      │   │   └── two_stage.py
      │   ├── __init__.py
      │   ├── layers
      │   │   ├── bbox_nms.py
      │   │   ├── __init__.py
      │   │   └── transformer.py
      │   ├── mask_heads
      │   │   ├── fcn_mask_head.py
      │   │   └── __init__.py
      │   ├── necks
      │   │   ├── fpn.py
      │   │   └── __init__.py
      │   └── roi_extractors
      │       ├── base_roi_extractor.py
      │       ├── __init__.py
      │       ├── roi_align.py
      │       └── single_level_roi_extractor.py
      ├── structures
      │       ├── bbox
      │       │   ├── __init__.py
      │       │   └── transforms.py
      │       └── mask
      │            ├── __init__.py
      │            └── mask_target.py
      ├── rtmdet_inst.py
      ├── torchvision
      │   ├── maskrcnn.py
      │   └── roi_head.py
      └── utils
          ├── __init__.py
          ├── roi_extractors
          ├── structures
          └── utils.py
      ```
  
      </td>
      <td>
  
      ```shell
      src/otx/algo/instance_segmentation/
      ├── backbones
      │   ├── __init__.py
      │   └── swin.py
      ├── heads
      │   ├── base_roi_head.py
      │   ├── bbox_head.py
      │   ├── convfc_bbox_head.py
      │   ├── custom_roi_head.py
      │   ├── fcn_mask_head.py
      │   ├── __init__.py
      │   ├── roi_head_tv.py
      │   ├── rpn_head.py
      │   ├── rtmdet_ins_head.py
      │   └── utils.py
      ├── __init__.py
      ├── layers
      │   ├── bbox_nms.py
      │   ├── __init__.py
      │   └── transformer.py
      ├── losses
      │   ├── accuracy.py
      │   ├── dice_loss.py
      │   └── __init__.py
      ├── maskrcnn.py
      ├── maskrcnn_tv.py
      ├── necks
      │   ├── fpn.py
      │   └── __init__.py
      ├── rtmdet_inst.py
      ├── two_stage.py
      └── utils
          ├── __init__.py
          ├── roi_extractors
          ├── structures
          └── utils.py
      ```
  
      </td>
      </tr>
      </table>
  

How to test

Checklist

• [ ] I have added unit tests to cover my changes.​
• [ ] I have added integration tests to cover my changes.​
• [ ] I have ran e2e tests and there is no issues.
• [ ] 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