Move Folders item closer to the top

Summary:
Move Folders item closer to the top in Dolphin's find panel. This seems like a more natural placment than after the document types.

Also re-order variable placement to maintain consistency

Test Plan:
Tested in KDE Neon; works. Before:

After:

Reviewers: Dolphin, elvisangelaccio

Reviewed By: Dolphin, elvisangelaccio

Subscribers: Dolphin

Differential Revision: https://phabricator.kde.org/D8132