Install qtlogo.svg as normal icon, so any QIconEngine can find it

Summary:
share/$app/pics is a place only checked by KIconEngine.

Also ensures consistency across icon logos installed by kdevelop

Reviewers: #kdevelop, kfunk

Reviewed By: #kdevelop, kfunk

Subscribers: kfunk, kdevelop-devel

Tags: #kdevelop

Differential Revision: https://phabricator.kde.org/D15621