Modularize payload formats used in Comms service framework

[MoralCode]

While the Comms service framework (which is currently buried in this repo under a more confusing name) uses a generalized (LinkPacket) implementation of CCSDS spacepacket that can be changed by missions relatively easily, there are still only a few hardcoded payload types that are part of KubOS (like graphql, all of them are documented in the kubos docs)

This makes it difficult for missions that want to implement other payload types

Some way to modularize this aspect of the comms framework would likely be quite useful for missions looking to use KubOS