- add storage for ringtone

- Refactor file load and save
- fix a size error in Canned Messages

src/modules/ExternalNotificationModule.h

@@ -28,7 +28,8 @@ class ExternalNotificationModule : public SinglePortModule, private concurrency:
 
     void stopNow();
 
-    char pwmRingtone[Constants_DATA_PAYLOAD_LEN] = "a:d=8,o=5,b=125:4d#6,a#,2d#6,16p,g#,4a#,4d#.,p,16g,16a#,d#6,a#,f6,2d#6,16p,c#.6,16c6,16a#,g#.,2a#";
+    void handleGetRingtone(const MeshPacket &req, AdminMessage *response);
+    void handleSetRingtone(const char *from_msg);
 
   protected:
     /** Called to handle a particular incoming message
@@ -37,6 +38,8 @@ class ExternalNotificationModule : public SinglePortModule, private concurrency:
     virtual ProcessMessage handleReceived(const MeshPacket &mp) override;
 
     virtual int32_t runOnce() override;
+
+    virtual AdminMessageHandleResult handleAdminMessageForModule(const MeshPacket &mp, AdminMessage *request, AdminMessage *response) override;
 };
 
 extern ExternalNotificationModule *externalNotificationModule;