Move "FM_GlobalData" back into private/local data structures

[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.
The FM_GlobalData object is only used within the FM app for private data storage. It should not be visible externally. However, it is currently defined here in the public fm_msg.h file:

FM/fsw/inc/fm_msg.h

Lines 542 to 594 in c856997

	typedef struct
	{
	FM_MonitorTable_t *MonitorTablePtr; /**< \brief File System Table Pointer */
	CFE_TBL_Handle_t MonitorTableHandle; /**< \brief File System Table Handle */
	CFE_SB_PipeId_t CmdPipe; /**< \brief cFE software bus command pipe */
	CFE_ES_TaskId_t ChildTaskID; /**< \brief Child task ID */
	osal_id_t ChildSemaphore; /**< \brief Child task wakeup counting semaphore */
	osal_id_t ChildQueueCountSem; /**< \brief Child queue counter mutex semaphore */
	uint8 ChildCmdCounter; /**< \brief Child task command success counter */
	uint8 ChildCmdErrCounter; /**< \brief Child task command error counter */
	uint8 ChildCmdWarnCounter; /**< \brief Child task command warning counter */
	uint8 ChildWriteIndex; /**< \brief Array index for next write to command args */
	uint8 ChildReadIndex; /**< \brief Array index for next read from command args */
	uint8 ChildQueueCount; /**< \brief Number of pending commands in queue */
	uint8 CommandCounter; /**< \brief Application command success counter */
	uint8 CommandErrCounter; /**< \brief Application command error counter */
	uint8 Spare8a; /**< \brief Placeholder for unused command warning counter */
	uint8 ChildCurrentCC; /**< \brief Command code currently executing */
	uint8 ChildPreviousCC; /**< \brief Command code previously executed */
	uint8 Spare8b; /**< \brief Structure alignment spare */
	uint32 FileStatTime; /**< \brief Modify time from most recent OS_stat */
	uint32 FileStatSize; /**< \brief File size from most recent OS_stat */
	uint32 FileStatMode; /**< \brief File mode from most recent OS_stat (OS_FILESTAT_MODE) */
	FM_DirListFileStats_t DirListFileStats; /**< \brief Get dir list to file statistics structure */
	FM_DirListPkt_t DirListPkt; /**< \brief Get dir list to packet telemetry packet */
	FM_MonitorReportPkt_t
	MonitorReportPkt; /**< \brief Telemetry packet reporting status of items in the monitor table */
	FM_FileInfoPkt_t FileInfoPkt; /**< \brief Get file info telemetry packet */
	FM_OpenFilesPkt_t OpenFilesPkt; /**< \brief Get open files telemetry packet */
	FM_HousekeepingPkt_t HousekeepingPkt; /**< \brief Application housekeeping telemetry packet */
	char ChildBuffer[FM_CHILD_FILE_BLOCK_SIZE]; /**< \brief Child task file I/O buffer */
	FM_ChildQueueEntry_t ChildQueue[FM_CHILD_QUEUE_DEPTH]; /**< \brief Child task command queue */
	#ifdef FM_INCLUDE_DECOMPRESS
	FS_LIB_Decompress_State_t DecompressState;
	#endif
	} FM_GlobalData_t;

Describe the solution you'd like
This should be defined in one of the internal header files, not in a public interface file.

Additional context
Public API should generally only be constants / #define's, and typedefs. API calls only for libraries - apps do not have public API calls. Extern data structs / globals should not be exposed in either apps or libs for a variety of reasons.

Requester Info
Joseph Hickey, Vantage Systems, Inc.