refactor: move to common Ory migration helpers

[aeneasr]

This patch brings Ory Keto SQL migrations in line with CLI patterns from Kraots and Hydra.

BREAKING CHANGE: Please update your migration scripts:

- keto migrate up
+ keto migrate sql up

- keto migrate down 2
+ keto migrate sql down --steps 2

- keto migrate status
+ keto migrate sql status

Related issue(s)

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
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  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

[aeneasr]

The migrate cmd in keto is a bit more complex, and since we already have down migrations there's no point really in investing more time