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

companion/src/modeledit/setup.cpp

@@ -488,7 +488,7 @@ void ModulePanel::update()
         ui->telemetryBaudrate->setField(module.ghost.telemetryBaudrate);
         break;
       case PULSES_PPM:
-        mask |= MASK_PPM_FIELDS | MASK_SBUSPPM_FIELDS| MASK_CHANNELS_RANGE| MASK_CHANNELS_COUNT;
+        mask |= MASK_SUBTYPES | MASK_PPM_FIELDS | MASK_SBUSPPM_FIELDS| MASK_CHANNELS_RANGE| MASK_CHANNELS_COUNT;
         if (IS_9XRPRO(board)) {
           mask |= MASK_OPEN_DRAIN;
         }
@@ -626,6 +626,9 @@ void ModulePanel::update()
     case PULSES_AFHDS3:
         numEntries = 4;
         break;
+    case PULSES_PPM:
+        numEntries = PPM_NUM_SUBTYPES;
+        break;
     default:
       break;
     }