AKModel: Nice-to-have features for slides

Core features are implemented. Open (nice to have) features are:

• Improve design (especially next AK placement and header font size)
• Add further fields or params (e.g., allow to choose/use accent color for the current event)
• Show progress bar on every slide
• Remove slot lengths for result presentation slides

added feature label

marked the checklist item Show progress bar on every slide as completed

Progressbar is already implemented but hardly visible -- yet, this is caused by the design currently used and not a thing that we can influence if we stick with that design.

marked this issue as related to #105

changed the description

mentioned in issue #139 (closed)

mentioned in commit 2e0bde29

mentioned in merge request !119 (merged)

mentioned in commit 7098b23c

changed milestone to %KIF 50,7

removed milestone %KIF 50,7

changed the description

Moved GUI into own ticket: #152 (closed)