feat: Support for ext. Multiplex MLink JR type module (#3352)

* introducing external MLink module telemetry as module PPM subtype

* implemented fix for sensor discovery display not showing all detected sensors (is in separate PR too)

implemented PPM subtypes in Companion

* add PPM subtype to model printer

finalize subtypes for PPM in Companion

* added logic to try to use HW UART with inverters turned off first (e.g. NV14), then, if not successfull use soft serial inverted (== uninverted data due to HW inverters on PCB)

changed start bit detection IRQ priority from 5 to the previous 0 (also in separate PR)

* extended telemetry timeout to 2s due to slow Mlink RSSI update rate

* changed the "NOTLM" sub-type texts to:

- "No Telem" for 128x64 (this is the max numbers of characters it can take)
- "No Telemetry" everything else including Companion

* Companion:

- lower case 1st charachter on PpmSubTypeStrings to ppmSubTypeStrings
- added telemetry hooks for ppmSubTypeStrings stringx

* simplified serial port initialization for MLink telemetry

* editorial change: corrected obsolete comment

radio/src/gui/128x64/model_setup.cpp

@@ -255,7 +255,7 @@ enum MenuModelSetupItems {
 
 inline uint8_t MODULE_TYPE_ROWS(int moduleIdx)
 {
-  if (isModuleXJT(moduleIdx) || isModuleISRM(moduleIdx) || isModuleR9MNonAccess(moduleIdx) || isModuleDSM2(moduleIdx))
+  if (isModuleXJT(moduleIdx) || isModuleISRM(moduleIdx) || isModuleR9MNonAccess(moduleIdx) || isModuleDSM2(moduleIdx) || isModulePPM(moduleIdx))
     return 1;
   else
     return 0;
@@ -1055,6 +1055,12 @@ void menuModelSetup(event_t event)
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_ISRM_RF_PROTOCOLS,
                              g_model.moduleData[INTERNAL_MODULE].subType,
                              menuHorizontalPosition == 1 ? attr : 0);
+#if defined(PPM)
+        else if (isModulePPM(moduleIdx))
+          lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_PPM_PROTOCOLS,
+                             g_model.moduleData[moduleIdx].subType,
+                             menuHorizontalPosition == 1 ? attr : 0);
+#endif
         else if (isModuleDSM2(moduleIdx))
           lcdDrawTextAtIndex(lcdNextPos + 3, y, STR_DSM_PROTOCOLS,
                              g_model.moduleData[moduleIdx].subType,
@@ -1129,6 +1135,12 @@ void menuModelSetup(event_t event)
                   CHECK_INCDEC_MODELVAR(event,
                                         g_model.moduleData[moduleIdx].subType,
                                         DSM2_PROTO_LP45, DSM2_PROTO_DSMX);
+#if defined(PPM)
+                } else if (isModulePPM(moduleIdx)) {
+                  CHECK_INCDEC_MODELVAR(event,
+                                        g_model.moduleData[moduleIdx].subType,
+                                        PPM_PROTO_TLM_NONE, PPM_PROTO_TLM_MLINK);
+#endif
                 } else if (isModuleR9MNonAccess(moduleIdx)) {
                   g_model.moduleData[moduleIdx].subType =
                       checkIncDec(event, g_model.moduleData[moduleIdx].subType,