port test_aggregates and test_hosts into nova v3 part1

This changeset only copies the v2 files into the appropriate v3
directories unchanged. This is being tried in order to make
reviewing of the porting easier as gerrit will display only what
is actually changed for v3 rather than entirely new files.

Partially implements blueprint nova-v3-api-tests

Change-Id: Idef3e36468ff2e7b7bd0517fdfa86e0b6c209e72
Merge "port test_aggregates and test_hosts into nova v3 part1"