cogl: Install cogl-trace.h and include from cogl.h

This is so that cogl-trace.h can start using things from cogl-macros.h,
and so that it doesn't leak cogl-config.h into the world, while exposing
it to e.g. gnome-shell so that it can make use of it as well. There is
no practical reason why we shouldn't just include cogl-trace.h via
cogl.h as we do with everything else.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/1059

src/backends/native/meta-backend-native.c

@@ -59,7 +59,7 @@
 #include "backends/native/meta-renderer-native.h"
 #include "backends/native/meta-seat-native.h"
 #include "backends/native/meta-stage-native.h"
-#include "cogl/cogl-trace.h"
+#include "cogl/cogl.h"
 #include "core/meta-border.h"
 #include "meta/main.h"