Adds notifiers to both volumeTypes and volumeTypeExtraSpecs

1. add notifier to create and delete volumeTypes
2. add notifier to create, update and delete volumeTypeExtraSpecs

Implements: notifiers for volumetypes and extra specs
Fixes: bug #1176259
Change-Id: I30fe6cb764e5fda7c876a8b7256d9b0c0f4a7fdd
Hide v1/v2 version entities in API when disabled

Fixes bug 1181413

Change-Id: Ia8aaa78a0e0d222c268e9ca780816eb1c26feb3f
Merge "Adds notifiers to both volumeTypes and volumeTypeExtraSpecs"
Merge "Hide v1/v2 version entities in API when disabled"