This changes the response for the createImage and createBackup
server action APIs to no longer return a Location header and instead
returns a json dict body with the snapshot image ID. This is done
in a new microversion.
Implements blueprint remove-create-image-location-header-response
Closes-Bug: #1679285
Change-Id: Idc899ee76b8265b1c9e0871b6c7c277424cdd442