port certificates tests 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: I55a91197dc7138e90dc59e8191c0209d9ce628c3
port certificates tests into nova v3 part2

this ports the certificates tests and corresponding client
into v3 version.

Partially implements blueprint nova-v3-api-tests

Change-Id: I28c19ac4b105940cafd1aa091bd52aa072961c0e
Merge "port certificates tests into nova v3 part1"
Merge "port certificates tests into nova v3 part2"