add sw graph

doc/SW-archi-graph.md

+```mermaid
+flowchart TB
+    A[ru_thread] --> RFin>block rx_rf] --> feprx
+    feprx --> half-slot --> end_feprx
+    feprx --> second-thread -- block_end_feprx --> end_feprx>feprx]
+    end_feprx --> rx_nr_prach_ru
+rx_nr_prach_ru -- block_queue --> resp_L1>resp L1]
+resp_L1 -- async launch --> rx_func
+resp_L1 -- immediate return --> RFin
+
+subgraph rxfunc
+rx_func_implem[rx_func] 
+    subgraph rxfuncbeg
+      handle_nr_slot_ind
+      --> rnti_to_remove-mgmt
+      --> L1_nr_prach_procedures
+      --> apply_nr_rotation_ul
+    end 
+    subgraph phy_procedures_gNB_uespec_RX
+      fill_ul_rb_mask
+      --> pucch(decode each gNB->pucch)
+      -->nr_fill_ul_indication
+      --> nr_ulsch_procedures
+      --> nr_ulsch_decoding
+      --> segInParallel[[all segments decode in parallel]]
+      --> barrier_end_of_ulsch_decoding
+    end 
+    subgraph NR_UL_indication
+      handle_nr_rach
+      --> handle_nr_uci
+      --> handle_nr_ulsch
+      --> gNB_dlsch_ulsch_scheduler
+      --> NR_Schedule_response
+    end 
+    rx_func_implem --> rxfuncbeg
+    rxfuncbeg --> phy_procedures_gNB_uespec_RX
+phy_procedures_gNB_uespec_RX --> NR_UL_indication
+-- block_queue --> L1_tx_free2>L1 tx free]
+-- async launch --> tx_func
+L1_tx_free2 -- send_msg --> rsp((resp_L1))
+end 
+rx_func --> rxfunc
+
+
+subgraph tx
+    direction LR
+    subgraph tx_func2
+       phy_procedures_gNB_TX
+       --> dcitop[nr_generate dci top]
+       --> nr_generate_csi_rs
+       --> apply_nr_rotation
+       -- send_msg --> end_tx_func((L1_tx_out))
+    end
+    subgraph tx_reorder_thread
+        L1_tx_out>L1_tx_out]
+        --> reorder{re order} --> reorder
+        reorder --> ru_tx_func
+        reorder --> L1_tx_free((L1_tx_free))
+        ru_tx_func --> feptx_prec
+        --> feptx_ofdm
+    end 
+    tx_func2 --> tx_reorder_thread
+end
+```