Generate expected schemata for Maniphest

Summary:
Ref T1191.

  - Adds support for custom fields.
  - Adds support for partial indexes (indexes on a prefix of a column).
  - Drops old auxiliary storage table: this was moved to custom field storage about a year ago.
  - Drops old project table: this was moved to edges about two months ago.

Test Plan:
  - Viewed web UI, saw fewer issues.
  - Used `grep` to verify no readers/writers for storage or project table.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T1191

Differential Revision: https://secure.phabricator.com/D10526