Moved MetricsService to its own file

app/src/main/java/org/mozilla/fenix/components/metrics/Metrics.kt

@@ -506,15 +506,3 @@ sealed class Event {
         get() = null
 }
 
-enum class MetricServiceType {
-    Data, Marketing;
-}
-
-interface MetricsService {
-    val type: MetricServiceType
-
-    fun start()
-    fun stop()
-    fun track(event: Event)
-    fun shouldTrack(event: Event): Boolean
-}

app/src/main/java/org/mozilla/fenix/components/metrics/MetricsService.kt

@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.components.metrics
+
+enum class MetricServiceType {
+    Data, Marketing;
+}
+
+interface MetricsService {
+    val type: MetricServiceType
+
+    fun start()
+    fun stop()
+    fun track(event: Event)
+    fun shouldTrack(event: Event): Boolean
+}