Feature configuration scene (depends on #10)

helpers/radio_scanner_states.h

@@ -0,0 +1,7 @@
+// Enumeration of the possible states of sound, ending with the number of sound states.
+typedef enum {
+    SoundStateOFF,
+    SoundStateON,
+    SoundStateSquelch,
+    SoundStateNum
+} SoundState;

helpers/scanner_event.h

@@ -0,0 +1,13 @@
+#pragma once
+
+/**
+ * Enumeration of scanner events.
+ */
+typedef enum {
+    // Scanning
+    ScannerEventScanDirectionDown,
+    ScannerEventScanDirectionUp,
+    ScannerEventToggleScanning,
+    // Views
+    ScannerEventViewConfig,
+} ScannerEvent;