Remove commands not supported by Nova V3 API

Remove commands which are no longer supported by the Nova
V3 API and that we will definitely not be proxying to another
service. Removes:

- cloudpipe-list
- cloudpipe-create
- cloudpipe-configure
- coverage-start
- coverage-stop
- coverage-report
- coverage-reset

Partially implements blueprint v3-api

Change-Id: I366cd0233977c1b506d55de280188ecccda8188f
Merge "Remove commands not supported by Nova V3 API"