camera plugin: add option to rotate camera with right click

The camera rotation only takes effect when there are no menu entries.
This also adds an option to make the middle button then open the menu.

Co-authored-by: Wynadorn <Wynadorn@users.noreply.github.com>

runelite-api/src/main/java/net/runelite/api/VarPlayer.java

@@ -171,7 +171,12 @@ public enum VarPlayer
 
 	MUSIC_VOLUME(168),
 	SOUND_EFFECT_VOLUME(169),
-	AREA_EFFECT_VOLUME(872);
+	AREA_EFFECT_VOLUME(872),
+
+	/**
+	 * 0 = 2 buttons, 1 = 1 button
+	 */
+	MOUSE_BUTTONS(170);
 
 	private final int id;
 }