Add missing expected keys and uniqueness

Summary:
Ref T1191.

• Adds definitions for missing keys and keys with wrong uniqueness. Generally, I defined these before fixing the key query to actually pull all keys and support uniqueness.
• Moves "key uniqueness" to note severity; this is fixable (probably?) and there are no remaining issues.
• Moves "Missing Key" to note severity; missing keys are fixable and all remaining missing keys are really missing (either missing edge keys, or missing PHID keys):

• Moves "Surplus Key" to note seveirty; surplus keys are fixable all remaining surplus keys are really surplus (duplicate key in Harbormaster, key on unused column in Worker):

Test Plan:

• Vetted missing/surplus/unique messages.
• 146 issues remaining.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T1191

Differential Revision: https://secure.phabricator.com/D10590