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/mesh/http/ContentHandler.cpp

@@ -623,7 +623,7 @@ void handleReport(HTTPRequest *req, HTTPResponse *res)
     }
 
     // Helper lambda to create JSON array and clean up memory properly
-    auto createJSONArrayFromLog = [](uint32_t *logArray, int count) -> JSONValue * {
+    auto createJSONArrayFromLog = [](const uint32_t *logArray, int count) -> JSONValue * {
         JSONArray tempArray;
         for (int i = 0; i < count; i++) {
             tempArray.push_back(new JSONValue((int)logArray[i]));