Remove PostgreSQL tempest jobs from Zuul
Remove PostgreSQL tempest jobs from Zuul

* remove monasca-tempest-*-postgresql jobs
* rename monasca-tempest-*-mysql -> monasca-tempest-*-influxdb jobs
* move `database` var to parent job

Story: 2001650
Task: 6669

Change-Id: Iac2cd9520caa313f0b1dc99204001bbf40d76a04
Depends-On: https://review.openstack.org/550874

stackforge/monasca-api,stackforge/monasca-api,openstack/monasca-api,openstack/monasca-api,stackforge/monasca-api,openstack/monasca-api,stackforge/monasca-api