Implement new feed and subscriptions groups

- Introduce Groupie for easier lists implementations
- Use some of the new components of the Android Architecture libraries
- Add a bunch of icons for groups, using vectors, which still is
compatible with older APIs through the compatibility layer

app/build.gradle

@@ -79,6 +79,11 @@ android {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
+
+    // Required and used only by groupie
+    androidExtensions {
+        experimental = true
+    }
 }
 
 ext {
@@ -111,6 +116,13 @@ dependencies {
     implementation "androidx.cardview:cardview:${androidxLibVersion}"
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
 
+    implementation 'com.xwray:groupie:2.3.0'
+    implementation 'com.xwray:groupie-kotlin-android-extensions:2.3.0'
+
+    implementation 'androidx.lifecycle:lifecycle-livedata:2.0.0'
+    implementation 'androidx.lifecycle:lifecycle-viewmodel:2.0.0'
+    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'
+
     // Originally in NewPipeExtractor
     implementation 'com.grack:nanojson:1.1'
     implementation 'org.jsoup:jsoup:1.9.2'