feat: add template value for kratos metric path

[fleblay]

Add possibility to customize kratos endpoint path for prometheus (the same way it is possible to do so in HYDRA)

Related Issue or Design Document

Checklist

• [ x] I have read the contributing guidelines and signed the CLA.
• [ x] I have referenced an issue containing the design document if my change introduces a new feature.
• [ x] I have read the security policy.
• [ x] 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 approval (please contact security@ory.sh) from the maintainers to push the changes.
• [ x] I have added tests that prove my fix is effective or that my feature works.
• [ x] I have added the necessary documentation within the code base (if appropriate).

Further comments

[Demonsthere]

Please update the values in hacks/values to override the default, we want the CI to test if the overloaded config generates a valid manifest

[Demonsthere]

LGTM :)