In the UE, we wish to handle ^C in the UE to send a message before
terminating, so we allow custom wait handlers to implement such
functionality. Use itti_wait_tasks_unblock() to unblock
itti_wait_tasks_end().

Also, implement itti_wait_tasks_end() using semaphores, as signals are
not async-signal-safe (and therefore should not be used in a signal
handler).

integration_2023_w12

See merge request oai/openairinterface5g!2030

* !1957 UL improvements for 2-layers
* !2016 int32_t to c16_t conversion
* !2028 Fix ue capability config files
* !2022 NR dlsim pmi input
* !2027 limiting SR periodicity according to scs
* !1985 Correct F1 RRC Message Transfer
* !2024 harmonize mac_CellGroupConfig RRC configuration
* !2026 Fix build by installing nrscope dependencies

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Add CI test: 3GPP G-FR1-A4-27, PUSCH Type B, 40 MHz BW, 30 kHz SCS, 2 RX Antennas Requirements Test, 2 layers

The message is never sent to the RRC. And this message is to be
forwarded by the DU to the UE, hence it should not even be handled by
the RRC (as the RRC in the CU sends it).