Maniphest - kill TYPE_PROJECTS

Summary: Fixes T5245. Migrate old TYPE_PROJECTS transaction to new style edge transactions. Kill remaining rendering code.

Test Plan:
issued some fun queries to get some old-style transaction in my install:

```
// go from nothing to 1
INSERT INTO maniphest_transaction (phid, authorPHID, objectPHID, viewPolicy, editPolicy, commentVersion, transactionType, oldValue, newValue, contentSource, metadata, dateCreated, dateModified)
VALUES ('PHID-XACT-TASK-000000000000000', 'PHID-USER-zo35vxnoi4bxqak6yqhc', 'PHID-TASK-hb5wphctibxxqryo6ssi', 'users', 'users', 0, 'projects', '[]', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx"]', '', '{}', 1419274578, 1419274578)

// go from 1 to 2
INSERT INTO maniphest_transaction (phid, authorPHID, objectPHID, viewPolicy, editPolicy, commentVersion, transactionType, oldValue, newValue, contentSource, metadata, dateCreated, dateModified)
VALUES ('PHID-XACT-TASK-111111111111111', 'PHID-USER-zo35vxnoi4bxqak6yqhc', 'PHID-TASK-hb5wphctibxxqryo6ssi', 'users', 'users', 0, 'projects', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx"]', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx", "PHID-PROJ-a7giqlyyfirqswg6gn6x"]', '', '{}', 1419274580, 1419274580)

// swap 1 for 1 with 2 in set
INSERT INTO maniphest_transaction (phid, authorPHID, objectPHID, viewPolicy, editPolicy, commentVersion, transactionType, oldValue, newValue, contentSource, metadata, dateCreated, dateModified)
VALUES ('PHID-XACT-TASK-222222222222222', 'PHID-USER-zo35vxnoi4bxqak6yqhc', 'PHID-TASK-hb5wphctibxxqryo6ssi', 'users', 'users', 0, 'projects', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx", "PHID-PROJ-a7giqlyyfirqswg6gn6x"]', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx", "PHID-PROJ-cety4gr55gpxzhwtrkhx"]', '', '{}', 1419274582, 1419274582)

// go from 2 to 1
INSERT INTO maniphest_transaction (phid, authorPHID, objectPHID, viewPolicy, editPolicy, commentVersion, transactionType, oldValue, newValue, contentSource, metadata, dateCreated, dateModified)
VALUES ('PHID-XACT-TASK-333333333333333', 'PHID-USER-zo35vxnoi4bxqak6yqhc', 'PHID-TASK-hb5wphctibxxqryo6ssi', 'users', 'users', 0, 'projects', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx", "PHID-PROJ-cety4gr55gpxzhwtrkhx"]', '["PHID-PROJ-4teaxbjk5okv7mdz2qlx"]', '', '{}', 1419274584, 1419274584)
```

took a screenshot. ran the migration script and compared the screenshots and things looked correctly migrated...!

old style:

{F255408}

new style:

{F255407}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T5245

Differential Revision: https://secure.phabricator.com/D11032