Remove duplicate header in a Payload message in the Metrics Protocol

[JONBRWN]

Currently, when sending over a Payload Message to the Monitoring Hub the Payload portion is preceded by a header and the Payload itself contains a header.

Initial payload size is unneeded and can be removed.

Requires updating HubProtocol decoder to accept new message structure.

[SeanTAllen]

@JONBRWN this seems like more than 1 issue jonathan.

also I'm unsure what this means, there is a lot of context missing here. could someone else start working on this?

[jtfmumm]

@JONBRWN Is this issue still relevant?

[JONBRWN]

@jtfmumm yes, although I wouldn't call it a bug as the protocol works fine. just some extra info passed along that we can remove