feat(controls): Hide header bar if no mouse movement

We hide the title bar similarly on how we hide the controls bar.

The difference between the header bar and the controls bar is that in
`Fullscreen` mode we don't display the header bar even if we have mouse
movement.

If a menu or sub-menu is open, but then the user makes no mouse
movement, then the menus will be hidden when the header bar is hidden.

I'm not sure how to handle the side panel, the `nav_bar`, what I call
"the playlist". I decided to not handle it's hiding based on mouse
movement because it is still displayed when we put the window in
`Fullscreen` mode.

Closes #37

src/main.rs

@@ -596,9 +596,11 @@ impl App {
                 .as_ref()
                 .map_or(false, |video| video.has_video())
         {
+            self.core.window.show_headerbar = true && !self.fullscreen;
             self.controls = true;
             self.controls_time = Instant::now();
         } else if self.controls && self.controls_time.elapsed() > CONTROLS_TIMEOUT {
+            self.core.window.show_headerbar = false;
             self.controls = false;
         }
         self.update_mpris_state();