Update various Asana odds-and-ends for "gid" API changes

Summary:
Ref T13453. Some of the Asana integrations also need API updates.

Depends on D20899.

Test Plan:

• Viewed "asana.workspace-id" in Config, got a sensible GID list.
• Created a revision, saw the associated Asana task get assigned.
• Pasted an Asana link I could view into a revision description, saw it Doorkeeper in the metadata.

Maniphest Tasks: T13453

Differential Revision: https://secure.phabricator.com/D20900