Inconsistent link colors and override of visited link color in feedback and alert components

[jorisleker]

We've reviewed the colors of our link styles to make them pass accessibility requirements.

The colors should be updated as follows:

• [x] link default: #155EEF
• [x] link hover: #004EEB
• [x] link active: #0040C1
• [x] link visited: #6927DA

Also see definition in Figma

The colors apply for all links in texts (not in buttons).

There is one exception. In feedback and alert components (red/yellow/green or blue background) the visited state of links should use the same color as the default state. Hover and active colors should override the visited color.

Acceptance criteria:

• [x] color of links adhere to scheme defined in this ticket
• [x] style of visited links in feedback and alert elements is same as non visited links
• [x] hover and active states always override visited state
• [x] style of visited links on Controleren en opslaan page is same as non visited links

Example of link in feedback component in Figma

[jorisleker]

Link colors are added in https://github.com/kiesraad/abacus/pull/303, work that remains to be done is updating styles in feedback and alert components