Fixed T23973 high dpi support
Summary:
+ added high DPI support in the base application
+ QmitkRenderWindow now regards devicePixelRatio to generate right positions for events
Test Plan: code review, test rendwer window interaction and if it looks nice(r) on high and low DPI.
Reviewers: O3 MITK Reviewer Group II, kislinsk
Reviewed By: O3 MITK Reviewer Group II, kislinsk
Subscribers: a178n, kislinsk
Differential Revision: https://phabricator.mitk.org/D804