KAZOO-1902: move vm cleanup to cb_vmboxes

track timers for cleanup stages

status/0 for cleanup process's timers
KAZOO-1902: only refresh if the db is an account db
KAZOO-1902: cleanup the deletion of docs, finding IDs, revisions, etc
KAZOO-1902: cleanup timer tracking for cleanup pass

Remove old voicemails and metadata, defaulting to a month

fix formatting of DBs (or not, as appropriate)
KAZOO-1902: use macro for integer constant, open cached versions of
media docs
Merge pull request #324 from 2600hz/KAZOO-1902

Kazoo 1902