Move CircleCI to GitHub Actions

[fendor]

CircleCI has been tagging along for quite some time now. But it did cause a couple of issues, for example in #4282.

There is no apparent reason why we might want to have a separate CI for stack and cabal, so we should unify the CI and use only GitHub action.

A potential disadvantage is that the additional stack jobs might overspill our CI cache limit.

The cache sizein CircleCI is currently:

Found a cache from build 67987 at v4-stack-cache-arch1-linux-amd64-6_85-stackage-nightly-9H4jA_vWfu4DX2U+oJlCNgYnwmWpFeeSs1ich4bwKTc=
Size: 686 MiB
Cached paths:
  * /root/.stack

and

Found a cache from build 67986 at v4-stack-cache-arch1-linux-amd64-6_85-stackage-lts22-uMKE535wPCuBR3jwBD8F3A7WLxI4RRRP_JyQHhniH1w=
Size: 675 MiB
Cached paths:
* /root/.stack

That's definitely too much for our 10GB limit.

[michaelpj]

I thought we had an issue for this, and indeed there is #3086... which apparently I closed myself by mistake 😅