test-ui: Add filtering by type
test-ui: Add filtering by type

When performing a search, for those sources supporting it, users can restrict
the results by type.

MathieuDuponchelle/grilo,kyoushuu/grilo,jasuarez/grilo,jasuarez/grilo,grilofw/grilo,MathieuDuponchelle/grilo,grilofw/grilo,grilofw/grilo,kyoushuu/grilo,kyoushuu/grilo,jasuarez/grilo,GNOME/grilo,GNOME/grilo,kyoushuu/grilo,MathieuDuponchelle/grilo