Initial conversion of browse tabs to full Compose

TODO:
- Global search should launch a controller with the search textfield focused. This is pending a Compose rewrite of that screen.
- Better migrate sort UI
- Extensions search

app/src/main/res/layout/main_activity.xml

@@ -25,12 +25,6 @@
             android:layout_height="?attr/actionBarSize"
             android:theme="?attr/actionBarTheme" />
 
-        <com.google.android.material.tabs.TabLayout
-            android:id="@+id/tabs"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:visibility="gone" />
-
         <TextView
             android:id="@+id/downloaded_only"
             android:layout_width="match_parent"