Currently tools are licensed under GPL-EXCEPT so replase old LGPL21
license header with GPL-EXCEPT one. Also remove old & unused license
files

Task-number: QTBUG-57147
Change-Id: Idc9c2189ee76c38fefb54b2e4b3b2d3622d7b892
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>