Arrange docker: UI polish
Summary:
- New, more legible layout.
- The arrange controls work only with the Select Shapes Tool. If another tool is active, the docker displays a message instead of the buttons. (Fixes bug 394084.)
- Also fixes mismatched align icons (bug 399984).
BUG: 399984
BUG: 394084
Reviewers: Krita, rempt
Reviewed By: Krita, rempt
Subscribers: rempt
Tags: Krita
Differential Revision: https://phabricator.kde.org/D16902