CFE_MSG_GetSize doesn't initialize size on failure - static analysis

[skliper]

Is your feature request related to a problem? Please describe.
Should initialize all output parameters:

cFE/modules/msg/src/cfe_msg_ccsdspri.c

Lines 322 to 328 in 672b2dc

	int32 CFE_MSG_GetSize(const CFE_MSG_Message_t *MsgPtr, CFE_MSG_Size_t *Size)
	{
	if (MsgPtr == NULL || Size == NULL)
	{
	return CFE_MSG_BAD_ARGUMENT;
	}

Describe the solution you'd like
Initialize to 0
Scrub MSG API's to ensure documentation and implementation comply (set all outputs, and define in documentation)

Describe alternatives you've considered
None

Additional context
Static analysis warning

Requester Info
Jacob Hageman - NASA/GSFC

[skliper]

Also - CFE_MSG_GetTypeFromMsgId and CFE_MSG_GetType... full scrub still needed (likely many "getters")

[skliper]

Pending discussion on #1198 discussion, topic 2.

[skliper]

CCB:2021-03-17 - this can be a hard pattern to follow and add complexity based on the error, not really an issue with the newer API's that return status. Less logic to initialize where needed in the calling function to squash static analysis warnings.