MQRFH_* (Rules and formatting header structure)

See:

MQRFH_STRUC_ID "RFHb"
MQRFH_STRUC_ID_ARRAY 'R','F','H','b'
MQRFH_VERSION_1 1 X'00000001'
MQRFH_VERSION_2 2 X'00000002'
MQRFH_STRUC_LENGTH_FIXED 32 X'00000020'
MQRFH_STRUC_LENGTH_FIXED_2 36 X'00000024'