Updates to models from scrum on 4/4

Updates to models from scrum on 4/4

Moved ToscaPolicyIdentXxx classes from models-pdp to models-tosca,
and added methods to retrieve them from a ToscaPolicy.

Removed version and instance fields from PdpStatus.

Chose to leave "description" field in the PAP/PDP messages.  The
PDPs can ignore them or leave them null.  In a PdpUpdate message,
the description will be the description associated with the PdpGroup.
In a PdpStatus message, the PDP could choose to provide a description
of the PDP, itself (or the type of PDP).
Added comments to that effect.

Moved name, group, and subgroup fields into PdpMessage.

Fixed typos in comments.
Updated licenses.
Change "long" to "Long" in PdpUpdate.
Use lombok @ToString instead of override.

Fixed merge conflict.

Change-Id: Icd928f9a7630b838ad4b0b5556e899dc21b7872b
Issue-ID: POLICY-1542
Signed-off-by: Jim Hahn <jrh3@att.com>