Add config and data convert function for occlusion-aware-face-dataset

[jinwonkim93]

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Motivation

Please describe the motivation of this PR and the goal you want to achieve through this PR. Add config to enhance performance add dataset convert function for original CelebA-mask dataset

Modification

Please briefly describe what modification is made in this PR. add config change config file name to follow paper naming. add dataset convert file update prepare.md

BC-breaking (Optional)

Does the modification introduce changes that break the backward-compatibility of the downstream repos? If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMDet3D.
4. The documentation has been modified accordingly, like docstring or example tutorials.