Postgresql has been implemented differently from
all other guest agents.
This has been causing difficulties with maintenance
and future development of Trove design.
It has been decided (Newton midcycle) to bring the guest agent
in line with others.
This patch set merges all Postgres service modules into
App/Admin classes.
This also resolves 20 pylint issues related to mixin usage.
Change-Id: I1b12a5296c59e9d3b08bcf34ac196d16189d525e
7fd8801d8d