Implement snapshots for servers and volumes

This provides the snapshot facility for server and volume resources.

Implements: blueprint stack-snapshot
Co-Authored-By: ala.rezmerita@cloudwatt.com
Change-Id: Id5e63f1a0081e29dc84bd1b71f9d40ae672877f6
Add utility functions for Swift TempURLs

blueprint swiftsignal-resource

Change-Id: I88c78b74dfb3c23cf74831bda3a9bdc69df6162a
Add OS::Swift::Signal resource

blueprint swiftsignal-resource

Change-Id: I5ba523210aa9aefbf46eeaa0d95293608a820f95
Resolved server and instance status redundancy

Instance and server resource's _check_active() methods were
stripping off an extra '(STATUS)' string from the status.
This change moves the code of consistently handling status
to the nova client in heat. So, both the resources need not
perform any exra stuff to determine the status.

Change-Id: Ib527c001a2cdae90de1545ccdd56ad722c724d07
Merge "Add utility functions for Swift TempURLs"
Merge "Add OS::Swift::Signal resource"
Merge "Implement snapshots for servers and volumes"