feat: Add Prometheus monitoring to Public API

[mbonnell-wish]

Proposed changes

Currently, the Prometheus metrics middleware is only used on the Admin API. This PR adds it to the Public API, so that Public API requests may be monitored, as well.

Checklist

• I have read the contributing 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 green light (please contact
  security@ory.sh) 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

[aeneasr]

Awesome, thank you!

[mbonnell-wish]

Thanks for approving! When do you think we'll be able to publish another release? Having this monitoring would be very important for us.

[aeneasr]

This is a bit tricky because we had some breaking changes and are actually waiting for 0.6 to push the next release - which will take some time. In the meanwhile you can use make docker and push it to your own repo!

[mbonnell-wish]

This is a bit tricky because we had some breaking changes and are actually waiting for 0.6 to push the next release - which will take some time. In the meanwhile you can use make docker and push it to your own repo!

Sounds good, thanks