R1:a763f9510e76

Add some Drydock documentation plus "Test Configuration" for repository automation

Summary:
Ref T182. Ref T9252.

- Adds a "Test" repository operation that just runs `git status` to see if things work.
- Adds a button for it in Edit Repository.
- Shows operation status on the operation detail view to make this workflow work a little better.
- Adds a lot of words. Words words words words.

Test Plan:
- Tested repository operation.
- Read words.

Reviewers: chad

Reviewed By: chad

Maniphest…