Consider eliminating group/node/edge IDs altogether and allowing a flexible hiearchy using namespace/message_type/any_hiearchy

[wes-johnson]

This came from a list of suggestions in #432.

(note that this would not break existing apps given a new namespace for the next version of SpB)

[wes-johnson]

This was discussed by the Sparkplug dev team and will not be included in Sparkplug 4