feature: DocumentsProvider implementation

[yackers]

Summary

This PR implements the following feature:

• DocumentsProvider for specific folder

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Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Code style update (formatting, renaming).
• Refactoring (no functional changes, no api changes).
• Documentation content changes.
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• Other (please describe):

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Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

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Closing Issues

• Closes Custom DocumentsProvider #3, App own DocumentsProvider #2 issue

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