Deregistered images are now periodically cleaned up - EUCA-6962

Deregistered images are now cleaned up in the background with a
configurable period. Administrative users can list images in the
deregistered state by passing 'verbose' as an image identifier.

EUCA-6962
Resolve services without paths by using host names - EUCA-2679

Public SOAP and Query API services now resolve without paths when using
their host names.

An abstract SoapPipeline is added for common SOAP functionality. This
includes accepting messages based on the host header used in the
request when the path is empty. Existing SOAP pipelines are updated to
remove common functionality which is now in the superclass.

QueryPipeline is updated to accept messages based on the host header
when a path is not used.

EUCA-2679
Reduce logging level for monitoring enabled message - EUCA-7287

EUCA-7287
Merge remote-tracking branch 'origin/dev/sjones/EUCA-2679' into testing
Merge remote-tracking branch 'origin/dev/sjones/EUCA-6962' into testing
Merge remote-tracking branch 'origin/dev/sjones/EUCA-7287' into testing