R1:e5f3ad14e12d

Allow audit comments to be added from Diffusion

Summary:
This is intended to supplant the existing "audit edit" interface. I've changed
them to both drive down the same write pathway, but the UIs are still different.
I'll fully merge them in a future diff.

Add a comment box (like Maniphest and Differential) to Diffusion. When users
make comments, their comments appear on the commit. Any audits triggers they are
responsible for are updated to reflect actions they take, as well.

Currently, audits can only…