R1:900190b2fe3a

Add inline comments to Diffusion/Audit

Summary:
- Add inline comments to Audits, like Differential.
- Creates new storage for the comments in the Audits database.
- Creates a new PhabricatorAuditInlineComment class, similar to DifferentialInlineComment.
- Defines an Interface which Differential and Audit comments conform to.
- Makes consumers of DifferentialInlineComments consume objects which implement that interface instead.
- Adds save

NOTE: Some features are still missing! Wanted to cut…