Integration 2021 wk10

MR !1039 (merged) : 5G_NR_FDD_fix
MR !1054 (merged) : gNB_multi-threading_rework
MR !1063 (merged) : T_tracer__add_gnb_tracer
MR !1070 (merged) : nr_pdcp_improvements
MR !1076 (merged) : PBCHNRTCFIX
MR !973 (merged) : s1_subnormal
MR !1048 (merged) : develop_SA_RA