feat: OpenID Connect Dynamic Client Registration and OAuth2 Dynamic Client Registration Protocol

[aeneasr]

This feature adds first-class support for two IETF RFCs and one OpenID Spec:

• OpenID Connect Dynamic Client Registration 1.0
• OAuth 2.0 Dynamic Client Registration Protocol
• OAuth 2.0 Dynamic Client Registration Management Protocol

To enable this feature, which is disabled by default, set

oidc:
  dynamic_client_registration:
    enabled: true

in your Ory Hydra configuration. Once enabled, endpoints POST, GET, PUT, and DELETE for /connect/register will be available at the public port!

Closes #2568
Closes #2549

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@fjvierap thank you for the great PR! I have made some adjustments. In particular:

1. I reused the Client Auth method from fosite so we do not need to write our own
2. I update the specification use to have a bit clearer naming

This PR still needs work:

1. My fosite client auth changes are not yet done
2. We need to add more tests
3. We need to add documentation on how to use this feature

Would you still be willing to help even though I needed so long to get this PR merged? :) If not I will try to complete it over the next few days / weeks.

Closes #2568

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
  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

[codecov]

Codecov Report

Merging #2909 (489985f) into master (72837a1) will increase coverage by 0.30%.
The diff coverage is 78.22%.

@@            Coverage Diff             @@
##           master    #2909      +/-   ##
==========================================
+ Coverage   77.95%   78.26%   +0.30%     
==========================================
  Files         110      110              
  Lines        7636     7731      +95     
==========================================
+ Hits         5953     6051      +98     
+ Misses       1266     1265       -1     
+ Partials      417      415       -2     

Impacted Files	Coverage Δ
client/client.go	81.25% <ø> (ø)
driver/registry_base.go	90.77% <33.33%> (-0.68%)	⬇️
client/handler.go	79.18% <77.87%> (+16.68%)	⬆️
client/validator.go	72.38% <100.00%> (+3.69%)	⬆️
driver/config/provider.go	89.40% <100.00%> (+0.09%)	⬆️
persistence/sql/persister_oauth2.go	80.85% <0.00%> (-0.86%)	⬇️
persistence/sql/persister_client.go	88.00% <0.00%> (+8.00%)	⬆️

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[aeneasr]

@fjvierap thank you for your hard work!