Murano provides support for attaching Cinder volumes to instances and
booting instances from existing volumes. However, there is no way for
a user to select an existing volume (or volume snapshot) using the
murano dynamic UI.
This patch provides a way to show and select available volumes or
volume snapshots.
Change-Id: Ic99443384180c8d0df33e2b7c15b8e56cd086da3
Implements: blueprint volume-selection-ui-element