Add 'flavor find' and 'qserver create' commands

* 'flavor find' searches for flavors matching a set of criteria
  (This should eventually be merged into flavor list)
* 'qserver create' is a 'server create' derivative that uses additional
  options to specify the server to create.  Initially this is to
  add --ram, --disk and --vcpus options to find a matching flavor rather
  than requiring a known flavor name or ID.  If --flavor is present
  (it is temporarily still required) it will be used in case the
  criteria fail to find a match.