Port all resources to new resource data methods

Change-Id: I9f7e984f5224cee16a2ffd3e9d6b118304766701
Related-Bug: #1306743
Merge "Port all resources to new resource data methods"
Use better validation in Volume resources

Currently the Volume resources have (almost) no required properties,
which is somewhat misleading, as some of them are actually required
but mutually exclusive (e.g. SIZE and BACKUP_ID).

This patch adds additional validation that minimal neccessary combination of
properties is present and updates schema description strings
to better stress mutual exclusiveness of those parameters.

Change-Id: I0ccd2061a7d0e06d10bb132c4f223cace3b98ae1