Refactored some resources, centralised Firebase topics by creating an emun 'Topic'

app/src/main/java/com/denizd/substitutionplan/data/DataFetcher.kt

@@ -231,7 +231,7 @@ internal class DataFetcher(isPlan: Boolean, isMenu: Boolean, isJobService: Boole
             val notification = NotificationCompat.Builder(context, HelperFunctions.notificationChannelId)
                 .setStyle(NotificationCompat.DecoratedCustomViewStyle())
                 .setCustomContentView(notificationLayout)
-                .setSmallIcon(R.drawable.ic_avh)
+                .setSmallIcon(R.drawable.ic_avhlogo)
                 .setContentIntent(openAppPending)
                 .setAutoCancel(true)
                 .setColor(ContextCompat.getColor(context, R.color.colorAccent))

app/src/main/java/com/denizd/substitutionplan/data/Topic.kt

@@ -0,0 +1,8 @@
+package com.denizd.substitutionplan.data
+
+internal enum class Topic(val tag: String) {
+    ANDROID("substitutions-android"),
+    BROADCAST("substitutions-broadcast"),
+    IOS("substitutions-ios"),
+    DEVELOPMENT("substitutions-debug")
+}