Flesh out the container REST API a tiny bit

Get the following test cases working
HTTP GET /v1/containers/ - get all containers
HTTP GET /v1/containers/xyz - get a single container
HTTP POST /v1/containers/ - create a new container
HTTP PUT /v1/containers/ - update a container
HTTP DELETE /v1/containers/xyz - delete a single container

Change-Id: Iaafddac89b9cedd3524727605cc420992268cd48