Mentorship Team Info Update

[4mber]

On the Community-Teams.md, the Mentorship Team section needs to be updated with:

1. Requirements to join,
2. and a link to the Mentorship Team Roadmap folder within OM's Roadmap repo.

No. 2 will mean creating a folder within OM's Roadmap repo for the Mentorship Team, which should include a README describing what the Mentorship Team is (check out the Writing Team roadmap in that repo for an example), and any docs we want to share with the community.

Docs that are generally set and probably won't change in major ways in the near future should be transferred to .md files, but links that are still being worked on collaboratively can be linked out to their respective Google Docs/Sheets/AirTables/Trellos/etc.

[4mber]

The reason to do this is so that resources that we want to share with the community are discoverable, by the community (rather than just in a message or doc somewhere).