Deprecate misleading cli command 'resource-template'

Current 'resource-template' command is misleading as it's
providing template snippet for the 'resource-type' and not the
'resource'. This has been deprecated and a new command
'resource-type-template' added.

ex.
$heat resource-type-template -F json OS::Nova::KeyPair

Change-Id: I373e2fa3c7891d2488704975ffdfb6d9afa5059a
Closes-Bug: #1336306