monitor-config-manager: Support logical monitor transforms

Add support for rotated monitors. This is done per logical monitor, as
every monitor assigned to a logical monitor must be transformed in the
same way. This includes being transformed on the same level; e.g. if
the backend does not support transforming any monitor of a logical
monitor natively, then all monitors will be transformed using the
offscreen intermediate framebuffer.

https://bugzilla.gnome.org/show_bug.cgi?id=777732

src/backends/native/meta-cursor-renderer-native.c

@@ -249,6 +249,7 @@ update_monitor_crtc_cursor (MetaMonitor         *monitor,
 
   meta_monitor_calculate_crtc_pos (monitor, monitor_mode,
                                    monitor_crtc_mode->output,
+                                   META_MONITOR_TRANSFORM_NORMAL,
                                    &crtc_x, &crtc_y);
 
   scaled_crtc_rect = (MetaRectangle) {