feat: oauth intsropsection configurable timeout

[pike1212]

Related issue

#310

Proposed changes

Make http timeouts configurable in the oauth2 introspector

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 [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 necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

[aeneasr]

This looks pretty good, thank you! I have some ideas how to improve it.

[aeneasr]

Thank you!

[hefekranz]

hmm, I was trying to use this feature and it seems like this only works if pre_authorization is enabled?
Is there a specific reason for that?

https://github.com/pike1212/oathkeeper/blob/519dc8d25c48ff0cd39dcd4e05e69616126e0a26/pipeline/authn/authenticator_oauth2_introspection.go#L169

[aeneasr]

Yup, that's not correct - would you be open to fix this? :)

[hefekranz]

sure, can do :)