Misc Service cleanup (#9005)

* Simplify DownloadService wake lock handling

_isRunning is only modified in onCreate/onDestroy, so the listener
job is redundant.

* Drop superclass calls to Service.onCreate/onDestroy

From https://developer.android.com/guide/components/services
> Note: Unlike the activity lifecycle callback methods, you are not
> required to call the superclass implementation of these callback
> methods.

app/src/main/java/eu/kanade/tachiyomi/data/backup/BackupRestoreService.kt

@@ -74,8 +74,6 @@ class BackupRestoreService : Service() {
     private lateinit var notifier: BackupNotifier
 
     override fun onCreate() {
-        super.onCreate()
-
         scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
         notifier = BackupNotifier(this)
         wakeLock = acquireWakeLock(javaClass.name)
@@ -90,7 +88,6 @@ class BackupRestoreService : Service() {
 
     override fun onDestroy() {
         destroyJob()
-        super.onDestroy()
     }
 
     private fun destroyJob() {