Migrate to AndroidX (#2424)

* Migrate to AndroidX (automatic conversion by Android Studio)

* AndroidX dependency code updates

* Fix source preference reparenting

* fixes the androidx prefererences icon spacing issue

(cherry picked from commit b76a15d960ec2cdf771be16377db0348b66b3179)

* Fix source preference screen heading size/list padding

Co-authored-by: Carlos <cargo8005@gmail.com>

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadNotifier.kt

@@ -2,7 +2,7 @@ package eu.kanade.tachiyomi.data.download
 
 import android.content.Context
 import android.graphics.BitmapFactory
-import android.support.v4.app.NotificationCompat
+import androidx.core.app.NotificationCompat
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.download.model.Download
 import eu.kanade.tachiyomi.data.download.model.DownloadQueue

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadService.kt

@@ -9,7 +9,7 @@ import android.net.NetworkInfo.State.DISCONNECTED
 import android.os.Build
 import android.os.IBinder
 import android.os.PowerManager
-import android.support.v4.app.NotificationCompat
+import androidx.core.app.NotificationCompat
 import com.github.pwittchen.reactivenetwork.library.Connectivity
 import com.github.pwittchen.reactivenetwork.library.ReactiveNetwork
 import com.jakewharton.rxrelay.BehaviorRelay

app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt

@@ -351,7 +351,7 @@ class Downloader(
                 .map { response ->
                     val file = tmpDir.createFile("$filename.tmp")
                     try {
-                        response.body()!!.source().saveTo(file.openOutputStream())
+                        response.body!!.source().saveTo(file.openOutputStream())
                         val extension = getImageExtension(response, file)
                         file.renameTo("$filename.$extension")
                     } catch (e: Exception) {
@@ -374,7 +374,7 @@ class Downloader(
      */
     private fun getImageExtension(response: Response, file: UniFile): String {
         // Read content type if available.
-        val mime = response.body()?.contentType()?.let { ct -> "${ct.type()}/${ct.subtype()}" }
+        val mime = response.body?.contentType()?.let { ct -> "${ct.type}/${ct.subtype}" }
             // Else guess from the uri.
             ?: context.contentResolver.getType(file.uri)
             // Else read magic numbers.