Scan multiple hardcoded folders for applications and simulations, as well as the two custom paths that can still be set. Now, XMLs with the 'application' tags go in the Applications view and those with 'simulation' tags go in the Simulations view, no matter where they are located. Prevent adding the same folder twice.

Add a dedicated 'Simulations' tab that behaves exactly the same as the
'Applications' tab. Allow 'simulation=' instead of 'application=' for
clarity in the XMLs. Recent folders are saved under the tag name
(simulation/application), and this is also the default folder that will
be searched for XMLs.