fix a lot of low level cppcheck warnings (#9623)

* simplify the observer pattern, since all the called functions are const getters.
* use arduino macro over std: for numerical values and refactor local variables in drawScrollbar()
* oh, so Cppcheck actually complained about const pointers not being const.
* slowly getting out of ifdef hell
* fix inkHUD warnings as well
* last 2 check warnings
* git checks should fail on low defects from now on

src/modules/Telemetry/Sensor/PMSA003ISensor.cpp

@@ -86,7 +86,7 @@ bool PMSA003ISensor::getMetrics(meshtastic_Telemetry *measurement)
         return false;
     }
 
-    auto read16 = [](uint8_t *data, uint8_t idx) -> uint16_t { return (data[idx] << 8) | data[idx + 1]; };
+    auto read16 = [](const uint8_t *data, uint8_t idx) -> uint16_t { return (data[idx] << 8) | data[idx + 1]; };
 
     computedChecksum = 0;