feat: add property initialPath

[luciferes]

Summary

add property initialPath to specify the starting directory for the document picker

Test Plan

What's required for testing (prerequisites)?

N/A

What are the steps to reproduce (after prerequisites)?

N/A

Compatibility

OS	Implemented
iOS	✅
Android	✅

Checklist

• [x] I have tested this on a device and a simulator
• [x] I added the documentation in README.md
• [x] I updated the typed files (TS and Flow)

[bhavesh-kreeti]

@luciferes great work! in making the picker support the initial path.

Can we please resolve the comments and move the PR forward?

[vonovak]

Hello, upon taking another look on this, I see that this won't work. ACTION_GET_CONTENT has no support for specifying initial url, and on iOS, the url needs to be security-scoped.

I'm going to close this because it doesn't seem that it's going to get done in this PR.

Thank you for your time and effort! :)