Feature: Implemented Custom Ringtone Feature (#157)

* adding file_picker and audioplayers dependency

* adding the ringtone model

* adding methods for reading and writing custom ringtone status

* adding custom ringtone status enum, and outlined button theme to constants

* adding methods for playing and stoping ringtone in utils

* adding methods for reading, writing, and deleting ringtone data to isar provider

* adding the custom ringtone tile to settings view

* implemeting the logic for opening file picker, saving the ringtone, and getting the saved ringtone to settings controller

* modifying the play and stop alarm methods in the alarm controllers

* implementing the custom ringtone tile and dialog

lib/app/data/models/ringtone_model.dart

@@ -0,0 +1,15 @@
+import 'package:isar/isar.dart';
+
+part 'ringtone_model.g.dart';
+
+@collection
+class RingtoneModel {
+  Id isarId = Isar.autoIncrement;
+  late String ringtoneName;
+  late List<int> ringtoneData;
+
+  RingtoneModel({
+    required this.ringtoneName,
+    required this.ringtoneData,
+  });
+}