Use CFE pattern for command handler functions

[jphickey]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
CFE has an established pattern for message dispatch routines in that:

1. It returns a CFE_Status_t (standard return value)
2. It accepts a single argument which is a const pointer to the message, of the actual/unique message type (e.g. CFE_ES_NoopCmd_t, etc).

FM does not follow this pattern, its message processor functions return bool and they accept the generic CFE SB message buffer rather than the specific message type.

Describe the solution you'd like
Make FM follow the CFE pattern

Additional context
This makes every command handler prototype unique, so they cannot be inadvertently interchanged without a compile error (this is a good thing).

Requester Info
Joseph Hickey, Vantage Systems, Inc.