Intial work to add mysql support for director

* Changed director's config format to no use URIs
* Migrate now uses director's configure_db method
* Added drop foreign key constraint to an earlier migration file
* Renamed job template properties to director_db from postgres
* Updated jobs and package for mysql dependencies

[for #49306843]
PowerDNS and Bosh Registry mysql support

* Removed powerdns postgres replication
* Renamed properties to be COMPONENT.db for database properties
* Added db configuration tests for director and registry

[for #49306843]
Convert release database connection options properties to hashes

[#49306843]
Improve readability of deployment plan filter_properties