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/src/main/java/org/schabi/newpipe/util/ConstantsKt.kt

@@ -0,0 +1,6 @@
+package org.schabi.newpipe.util
+
+/**
+ * Default duration when using throttle functions across the app, in milliseconds.
+ */
+const val DEFAULT_THROTTLE_TIMEOUT = 120L

app/src/main/java/org/schabi/newpipe/util/NavigationHelper.java

@@ -343,9 +343,13 @@ public class NavigationHelper {
                 .commit();
     }
 
-    public static void openWhatsNewFragment(FragmentManager fragmentManager) {
+    public static void openFeedFragment(FragmentManager fragmentManager) {
+        openFeedFragment(fragmentManager, -1, null);
+    }
+
+    public static void openFeedFragment(FragmentManager fragmentManager, long groupId, @Nullable String groupName) {
         defaultTransaction(fragmentManager)
-                .replace(R.id.fragment_holder, new FeedFragment())
+                .replace(R.id.fragment_holder, FeedFragment.newInstance(groupId, groupName))
                 .addToBackStack(null)
                 .commit();
     }

app/src/main/java/org/schabi/newpipe/util/ThemeHelper.java

@@ -99,6 +99,17 @@ public class ThemeHelper {
         return isLightThemeSelected(context) ? R.style.LightDialogTheme : R.style.DarkDialogTheme;
     }
 
+    /**
+     * Return a min-width dialog theme styled according to the (default) selected theme.
+     *
+     * @param context context to get the selected theme
+     * @return the dialog style (the default one)
+     */
+    @StyleRes
+    public static int getMinWidthDialogTheme(Context context) {
+        return isLightThemeSelected(context) ? R.style.LightDialogMinWidthTheme : R.style.DarkDialogMinWidthTheme;
+    }
+
     /**
      * Return the selected theme styled according to the serviceId.
      *