Validation check if exceeding vol snapshot quota

Disables "Create Snapshot" action for each volume in the Volumes table,
if the Volume Snapshot Quota is already at max.
Appends "Quota Exceeded" to the action button for user feedback.
Extends "test_get_data" to account for new Cinder api call.
Adds "test_create_snapshot_button_disabled_when_quota_exceeded"
to make sure action button state is altered when snapshots used is equal
to max snapshots.

Change-Id: I56798869f5e870cef2dd81301330b83aade040d4
Closes-Bug: 1333481
Merge "Validation check if exceeding vol snapshot quota"