Get rid of cookies

[fhennig]

Having the cookies (and therefore the banner) is annoying, and maybe we don't even need them. Needs investigating.

I think the only cookie we're using is the matomo one. relevant code

[fhennig]

blocked by https://github.com/stackabletech/infrastructure/issues/142

Talk to Fabian about this.

[xeniape]

After talking with Fabian: Before the Matomo cookies can be removed, the "repeated visitors" functionality needs to be re-configured/removed/implemented somewhere else before that (currently in Matomo). Discussion needed.