[Documentation]: Have a work board for the contributors

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Page URL (type "NEW" for a new page suggestion)

NEW

### What's the documentation problem or suggestion?

I like very much to contribute to the android open source projects. I think it is useful for the contributors to have a work board or something like that. I found a good one in the Android Wikipedia app [here](https://phabricator.wikimedia.org/tag/wikipedia-android-app-backlog/)
In the Wikipedia app, contributors know that they can assign a task from Tech or Bug Back log to themself and start to work on it. It'll be very good to have the same idea in this repo as well.

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Review the contributor workflow for nowinandroid and compare it with the Wikipedia Android app backlog linked in the issue. Define where a contributor work board would live, how tasks could be claimed, and how it would be maintained; the issue is done only when the board and its usage guidance are established.

Written by the indexing model from the issue text.