[53309] Reduce configurable design variables

[HDinger]

Todo

In Administration / Design:

• The colour token Primary dark is removed. A darker variant for hover effects is calculated automatically
• Alternative colour tokens will be renamed to Primary button.
• The colour token Primary is removed as well. It is replaced by the new Primary button
  • Merge the button options "-alt-highlight" and "-highlight" into one "-primary" button style using the Primary button token.
  • Introduce an (internal) variable for highlighting controls (toggle buttons, datepicker selection etc). This will be calculated based on the link color.
• Link font will be renamed to Accent as it will be the base for other calculated variables (e.g for checked controls as the toggle)

Test checklist

• pre-defined Themes (Normal, Light, Dark, BIM)
• Custom design
• Fresh seed

https://community.openproject.org/projects/openproject/work_packages/53309/activity