Reference Airship manifests, CICD, and reference architecture.

Gerrit User 23186 be2e571974 Update patch set 2 ... Patch Set 2: It would be nice to add a README.rst to tools/gate explaining that this stuff is for downstream airship-ci. As we might want to add Zuul jobs later. Patch-set: 2		2018-08-15 20:42:10 +00:00