Implement fullscreen and quality selector

- Implement cache
- Abstract player
- Quality selector
- Fullscreen switcher
- Change some drawables

app/src/main/res/drawable/player_controls_bg.xml

@@ -1,8 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <shape xmlns:android="http://schemas.android.com/apk/res/android">
     <gradient
-        android:startColor="#a0000000"
-        android:centerColor="#26000000"
+        android:startColor="#8c000000"
         android:endColor="#00000000"
         android:angle="90"
         />

app/src/main/res/drawable/player_top_controls_bg.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+    <gradient
+        android:startColor="#8c000000"
+        android:endColor="#00000000"
+        android:angle="-90"
+        />
+</shape>