Rework visibility of the select button in the content view

This tries to address two problems:
1) when the geolocation query ends, an item gets inserted in the list
but if we are currently on another page we should not show the button so
we introduce a check with get_mapped()
2) if only the automatic location is present, then we should not show
the select button since the only action is delete and automatic clocks
cannot be deleted, so we introduce a separate can_select property