redefining max number of UEs for memory allocation. Using the PHYSIM macro, different allocations are used for phy_simulators and real-time modem.

Conflicts:
	cmake_targets/build_oai
	openair1/PHY/LTE_TRANSPORT/prach.c
	openair1/SCHED/phy_procedures_lte_ue.c
	targets/ARCH/COMMON/common_lib.h
	targets/RT/USER/lte-softmodem.c

- LMSSDR was not handled
- bad #if usage
- bad indentation

still not very clean, but better

	modified:   targets/COMMON/openairinterface5g_limits.h

In openairinterface5g many definitions in many layers of UE or eNB NB_MAX.
We created a file called openairinterface5g_limits.h
located at openairinterface5g_dir/targets/COMMON/ declaring the number max
of UE and eNB to be used in ALL layers depending on launching conditions
(LARGE_SCALE for example).