Support wikimetrics in vagrant

Changes to work in local setup with 'wiki' rather than 'enwiki' database.
Create databases for testing without clobbering dev dbs.
Make sure wikimetrics can work on offline mode regarding project_host_map.
Merge with master alembic changes.
Changed DB creation to include wiki_testing/wikimetrics_testing db.
Added testing config for initialization of celery when testing.
Cleaned up code and config.
Corrected issues with merge from master.
Added testing wikimetrics db to alembic generation.
Fixed tests.

Change-Id: I2a1b557da5aad53f939f8cf523e9b148c0debe5d