1.Add new entrypoint 'experimental', devstack will be
modified to support this.
2.Add controller Capsule
3.Add capsule create method
4.Refactor the code for _do_container_create
5.Add one capsule template
All capsule method in the API level will use:
/experimental/capsules API, apart from v1 API.
Part of blueprint introduce-compose
Change-Id: Ia031ee5beb48ec70dab6bb371944140d025a499b
Signed-off-by: Kevin Zhao <kevin.zhao@arm.com>
70020a9447