delegate container_create to physical hosts

This eliminates the use of hostvars[] in container creation which allows
us to use templated variables, necessary for the fix for #1399427 which
has already been merged.

Notes:
  * Creates containers in parallel.
  * Improves flexability in container create as a specific group or container
    can be targeted on the CLI.
  * Syntax clean up.
  * Adds option to specify the container volume group name.
  * Removes the "ignored" failure note when running in an environment that does
    not use LVM and have an LXC volume group.

Closes-Bug: #1399427
Change-Id: I4270a9d11039b62d631f82d24de7cc87d5f142c9
Merge "delegate container_create to physical hosts"