Panel service needs to know coordinates of the indicators

[Rodrigo Moya]

For implementing AtkComponent interface for some of the a11y objects in the panel service, we need to know the coordinates where the indicators are shown on the screen, so since, from what Neil told me, was planned for other features, we need to add it now.

The information would just be sent from unity after we deal with the Sync signal, basically a method on the service like "SyncGeometries", which, in the same order and using the same ids, sends back a struct like { char *entry_id, int x ,int y, int width, int height)

The plan to send the coordinates was due to the need, in the panel service, to know where to display the popup menus, so when adding this, we probably want to get rid of the code that sends back the pointer co-ords when a menu is open.