Major re-amp of client (See points)

* Uses auth plugins - is still WIP but using a working one for now.
  Will have to re-visit this once it lands in keystone / oslo update.
* Resource and Manager abstractions.
* Python 3 compatability.
* Split the API/Bindings and Shell code
* Use entrypoints for versions
* Mandatory options are now positional
  Example: libra <cmd> --id <id> is now libra <cmd> <id>

Change-Id: I42275cc88be5689f040864e195e48c5ebacb2cea