feat: implement crypt(3) hashers

[indietyp]

Implement crypt(3) based hashers.

This PR implements md5crypt, sha256crypt, sha512crypt, which are considered legacy (like md5), but are used in legacy systems looking to convert to ory. They use the existing format of crypt(5) (which is compliant to PHC).

Related issue(s)

• Ability to import crypt(3) hashes #3291

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  [email protected]) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

[CLAassistant]

All committers have signed the CLA.

[hperl]

Thanks for your contribution. This looks really good already, I just have two minor comments below.

[hperl]

Thanks for the changes, LGTM! 🎉

[vinckr]

Hello @indietyp @hperl

Would it be good to have docs for this? At least seems good IMO to mention it here.

[hperl]

Docs are already done :)
ory/docs#1426

[vinckr]

Oh missed that, thanks!