This is another case of a weird pattern where an object would
connect it's own signal to the slot of a different object.
There seems to be no reason why the former couldn't simply
call the latter.
Remove the [start|stop]FilterDiveSite signals of LocationInformationWidget
and call the corresponding functions of MultiFilterSortModel directly.
While doing so, replace the UUID argument by a pointer-to-divesite.
It will be converted anyway right at the beginning of the function.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>