Set TripleO CI control variables based on job type

Currently if we change any of these variables we won't know if we did
the right thing until it's merged into openstack-infra/config. Moving
these into tripleo-ci will give us the ability to make changes and have
CI validate we did the correct thing. It will also ensure all jobs run
with the same defaults (e.g. currently not all the jobs run with
USE_CIRROS=1 which I don't think was ever intended).

This commit should be merged before its counterpart in the infra/config
repository I58462d3ce3e63ea190c95e2a210c087c978c7d16

Change-Id: I5ed1a7bb473d9f7183b3a036702a1c71bfc5870d
Merge "Set TripleO CI control variables based on job type"