Program menu items should be easier to add after installing a program

Make it possible to add a program to the application menu directly from the program listing in Vineyard. *DONE*

Doing this from the Programs page is however, the only way of doing it. Ideally VIneyard would provide a list of found menu items after running an installer (or a program from vineyard-launcher) and ask which should be added - and make setting category available easily from that dialog as well.