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/pulses/pulses.cpp

@@ -263,7 +263,16 @@ uint8_t getRequiredProtocol(uint8_t module)
 
   switch (getModuleType(module)) {
     case MODULE_TYPE_PPM:
-      protocol = PROTOCOL_CHANNELS_PPM;
+      switch (g_model.moduleData[module].subType) {
+        case PPM_PROTO_TLM_NONE: 
+          protocol = PROTOCOL_CHANNELS_PPM;
+          break;
+        case PPM_PROTO_TLM_MLINK:
+          protocol = PROTOCOL_CHANNELS_PPM_MLINK;
+          break;
+        default:
+          protocol = PROTOCOL_CHANNELS_PPM;
+      }
       break;
 
     case MODULE_TYPE_XJT_PXX1:
@@ -462,6 +471,9 @@ static void pulsesEnableModule(uint8_t module, uint8_t protocol)
   case PROTOCOL_CHANNELS_PPM:
       _init_module(module, &PpmDriver);
       break;
+  case PROTOCOL_CHANNELS_PPM_MLINK:
+      _init_module(module, &PpmDriverMLink);
+      break;  
 #endif
 
 #if defined(INTERNAL_MODULE_AFHDS2A) && defined(AFHDS2)