dock assets for other positions (#234)

* add dock assets for various other positions

* Add Multitasking-panel assets and move them into folders:

- separate panel and dock assets and move them into their folders
- separate appearance and multitaking assets and move them into their folders

* update assets path in pubspec.yaml

* Optimize assets with svgo

* Optimize all assets

* Update image paths

Co-authored-by: Paul Kepinski <[email protected]>
Co-authored-by: Feichtmeier <[email protected]>

Author: 3 people