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/TraceRouteModule.cpp

@@ -266,7 +266,7 @@ void TraceRouteModule::alterReceivedProtobuf(meshtastic_MeshPacket &p, meshtasti
     }
 }
 
-void TraceRouteModule::updateNextHops(meshtastic_MeshPacket &p, meshtastic_RouteDiscovery *r)
+void TraceRouteModule::updateNextHops(const meshtastic_MeshPacket &p, meshtastic_RouteDiscovery *r)
 {
     // E.g. if the route is A->B->C->D and we are B, we can set C as next-hop for C and D
     // Similarly, if we are C, we can set D as next-hop for D