feat(gui): achievements (#806)

* feat(gui): achievement badges

* feat(gui): define achievement levels

* feat(gui): display achievements in statistics view

* feat(gui): show count on annotation cards

* feat(gui): keep track of annotation removals

* feat(gui): keep track of elements marked as complete

* feat(gui): keep track of annotations marked as correct

* feat(gui): keep track of annotations created/changed

* refactor(gui): reduce code duplication

* refactor(gui): improve file structure

* feat(gui): show toast for achievements

* feat(gui): don't show achievement toasts when UI is loading

* fix(gui): build error

* style: apply automatic fixes of linters

* feat(gui): single column grid on smaller screens

* fix(gui): increment of counter when "Mark as Correct" is toggled off

* style: apply automatic fixes of linters

Co-authored-by: lars-reimann <[email protected]>

Author: lars-reimann