Add database-api publishing jobs to trove

The database-api files are moving into the trove repository. Add the
usual api project gating and publishing jobs for the documentation files.

This depends on https://review.openstack.org/#/c/87807/ (merged now).

Change-Id: I53926a219a583a346350fdcc235a69f9f4865b0d
Merge "Add database-api publishing jobs to trove"