C2MS11 — Clarify Text Associated with Simple Service Req/Resp

After discussion in C2MS RTF in Orlando 2023 Tech Meetings, we determined to clarify or clean up some text with Simple Service Request and Response messages as follows:

• Say it’s not intended to be long-term but for quick on-boarding. Services meant for long-term use should create their own message set apart from Simple Service
• Say that we intend to rework or replace Simple Service at some point in a future release.
• Consider removing text about using it for a publish mode

Note that the response message as it is lacks the Service-Group that was specified in the request message. This lack makes it impossible to correctly correlate a response to a request that did specify Service-Group. However, because we intend to 'rework' these messages in a future release, we won't make this change at present.

A related issue will be created to replace simple service and deprecate current simple service, but will be deferred to later.