libcamera: Move EventDispatcher to internal API

There's no user of the EventDispatcher (and the related EventNotifier
and Timer classes) outside of libcamera. Move those classes to the
internal API.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

test/timer-thread.cpp

@@ -8,10 +8,9 @@
 #include <chrono>
 #include <iostream>
 
-#include <libcamera/event_dispatcher.h>
-#include <libcamera/timer.h>
-
+#include "libcamera/internal/event_dispatcher.h"
 #include "libcamera/internal/thread.h"
+#include "libcamera/internal/timer.h"
 
 #include "test.h"