Move bosh templates to CC that allow spliting single CC job to multiple ones.

* This is to reduce duplicates when we one to re-use configs in multiple jobs.

[#65336602]

Signed-off-by: Phan Le <ple@pivotallabs.com>
Add spec/README.md to describe role of specific test folders

To start, only documented spec/acceptance and
spec/acceptance/broker_api_compatibility, as these two folders have
caused confusion recently.