Convert CertState to a type family

[Lucsanszky]

Description

Resolves #4693

Checklist

• Commits in meaningful sequence and with useful messages
• Tests added or updated when needed
• CHANGELOG.md files updated for packages with externally visible changes
  
  New section is never added with the code changes. (See RELEASING.md)
• Versions updated in .cabal and CHANGELOG.md files when necessary, according to the
  versioning process.
• Version bounds in .cabal files updated when necessary
  
  If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• Code formatted (use scripts/fourmolize.sh)
• Cabal files formatted (use scripts/cabal-format.sh)
• hie.yaml updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[lehins]

I did a quick skim over the PR and it looks awesome.
There is one important point that I made that will need to be address that has to do with a common issue of changes getting lost during rebasing, but that shouldn't be too hard.
I'll do a proper review once the PR is out of the Draft state.

[Lucsanszky]

Finally, this is now ready for review. I opted not to detail every little change in the changelogs but rather indicate the affected packages that CertState was converted to a type family.

[lehins]

This a very nice piece of work.
Thank you!

I've created a follow up ticket that will track the other half of the work that needs to be done with respect to CertState