-Fixed memory leak on rogue observable in history fragment.

-Removed stream id from playlist stream join table since only foreign constraint is needed.
-Added bar to playlist control UI.
-Modified local playlist fragment to no longer save when out of focus.

app/src/main/java/org/schabi/newpipe/fragments/local/LocalPlaylistFragment.java

@@ -469,7 +469,6 @@ public class LocalPlaylistFragment extends BaseLocalListFragment<List<PlaylistSt
         return debouncedSaveSignal
                 .debounce(SAVE_DEBOUNCE_MILLIS, TimeUnit.MILLISECONDS)
                 .observeOn(AndroidSchedulers.mainThread())
-                .doOnDispose(this::saveJoin)
                 .subscribe(ignored -> saveJoin());
     }