Fixes #228 (Adds ability to remove active_model bound to a specific node)

Adds ability to remove a specific active_model instance, based on the hardware_id (SMBIOS UUID)
or the Hanlon-assigned UUID of the node  that active_model instance is bound to. Also adds the
ability to get a specific active_model instance based on those same two values (either the
hardware_id or the Hanlon-assigned UUID of the node that active_model instance is bound
to...previously only a search by hardware_id of the bound node was supported).
Changed long form of flag used to specify the Node UUID to '--node_uuid'
(instead of the '--nuuid' form used previously)
change name of query parameter used when searching for an active_model instance
based on the (Hanlon-assigned) UUID of the node it's bound to from 'uuid' to
'node_uuid' for clarity
Merge pull request #233 from tjmcs/tb/remove-active-model-by-uuid

Fixes #228 (Adds ability to remove active_model bound to a node)