RFC 7591 dynamic client registration protocol

[n2ygk]

Is your feature request related to a problem? Please describe.

Dynamic client registration is not support.

Describe the solution you'd like

Implement RFC 7591 dynamic client registration endpoint.

Describe alternatives you've considered

Additional context

[spinus]

Isn't that duplicate of #670?

[n2ygk]

All that's needed is a volunteer to submit the PR :-)