This change is done in preparation to add the header unpack functions to the VNF and PNF structures as function pointers, used to peek the message headers prior to processing.
Add a faux fapi_nr_p7_message_header_unpack with the same signature as nfapi_nr_p7_message_header_unpack, to be used for the P7 header unpack function pointer.
Changed parameter in unpack function to be inline with other unpack functions.
Changed nfapi_p7_allocate call to calloc to avoid dependency to NFAPI_LIB.
Added unitary test for RACH.indication( test pack/unpack, free, copy and compare )
Added constant NFAPI_NR_RACH_IND_MAX_PDU to follow constants related to other P7 messages limiting the maximum number of PDUs to use.
Removed now unneeded dependency to NFAPI_LIB and NFAPI_USER_LIB