[WFLY-490][WFLY-1756] Include access control for read-operation-description
[WFLY-490] Some minor clean up and removal of unused imports, variables and methods in test cases.
[WFLY-2087] / [WFLY-490] Add a new constraint to ensure that the roles SUPERUSER and AUDITOR can only be updated by SUPERUSER.
[WFLY-2171] Use deployment unit processors to register mod_cluster metrics
[WFLY-2090] Rework metrics to be HttpHandlers instead of ThreadSetupActions since they can run multiple times and cause ISE
[WFLY-2171] Introduce UndertowAttachments class to shelter homeless AttachmentKeys used for mod_cluster integration