Issue Description:
When a Bridge is updated it is entered into the normal lifecycle of ACCEPTED -> PREPARING -> PROVISIONING -> READY. It is not possible for the front-end to disambiguate this from creating a new resource. Furthermore the back-end prevents various operations while the Bridge is not READY such as listing Processor's, adding a new Processor or deleting one.

This is undesirable since the only permitted update to a Bridge is for the Error Handler; and it is unreasonable to restrict listing Processor's etc on a Bridge merely because the Error Handler is being updated (when an Error Handler is updated the Bridge is put back into ACCEPTED state until the Error Handler is READY and the Bridge moves to READY).

Adding UPDATING to Bridge's would allow disambiguation of creating and updating allowing lifting of operational restrictions when the Error Handler is updating.

Acceptance Criteria:

• A Bridge supports UPDATING status and consumers of the backend-end API are able to list Processor's on a Bridge etc whilst the Bridge is being updated.
• This is available for the v2 API only, as the v1 API is considered frozen and will not be used by the UI