Fix ProblemsView tabs order

Summary:
The patch fixes (random) order of tabs in ProblemsView with follows settings:

1. First tab always used by "Parser" model due it's the most important problem listing, it should be at the front (K.Funk idea at KDevelop IRC channel).

2. Other tabs are alphabetically ordered.

Test Plan: Tested on master branch. Manually plugins loading/unloading don't break the order.

Reviewers: kfunk, KDevelop

Reviewed By: kfunk, KDevelop

Subscribers: kdevelop-devel

Differential Revision: https://phabricator.kde.org/D3125