Adding Volume MetaData Functions

Adding get, getAll and find functions for volume metadata.
Added two new enumerations for CHAP initiator and target.
Changed metadata functions to use REST API calls instead of SSH.
Updated the minimum required HP 3PAR build version to 3.1.3.230.
Added support for volume metadata REST API calls in the flask server.

Change-Id: Ib1d8cabd96b2da6d854d898b210d705d451ff797