Settings/info page

[jonasKjellerup]

We should add a page that allows the user to set various preferences.

This should include at minimum:

• [ ] Theme selection (#18)
• [ ] Active stregsystem profile (#7)
• [ ] Option to clear cache

Additional it may be convenient to include various information for debugging and bug reporting.

• [ ] Browser information (vendor+version)
• [ ] Build version
• [ ] Link to repo page with info in regards to reporting bugs.

[krestenlaust]

Regarding theme selection, having an option light/dark-mode to sync with system as well, would be cool