Add a new AQS testing environment to play with Cassandra settings before production.
Not sure if this is the best way to do it but the idea is to use the aqs role for
aqs100[456] and to override the cassandra/restbase hieradata settings with host level
specific ones. This should allow a testing replica of AQS without affecting the
existing cluster.
Bug: T124314
Change-Id: I504a9536c28ee839ea9a11f2f5950f0742bb94b0