Improved GPS Settings app and GPS service (#222)

- Fixes and improvements to `GpsSettings` app, `GpsDevice` and `GpsService`
- Implemented location/GPS statusbar icon
- Added app icon
- Added support for other GPS models (based on Meshtastic code)

TactilityCore/Source/StringUtils.cpp

@@ -1,6 +1,7 @@
 #include "Tactility/StringUtils.h"
 
 #include <cstring>
+#include <ranges>
 #include <sstream>
 #include <string>
 
@@ -80,4 +81,19 @@ std::string removeFileExtension(const std::string& input) {
     }
 }
 
+bool isAsciiHexString(const std::string& input) {
+    // Find invalid characters
+    return std::ranges::views::filter(input, [](char character){
+        if (
+           (('0' <= character) && ('9' >= character)) ||
+           (('a' <= character) && ('f' >= character)) ||
+           (('A' <= character) && ('F' >= character))
+        ) {
+            return false;
+        } else {
+            return true;
+        }
+    }).empty();
+}
+
 } // namespace