[Feature Request] Add some missing metadata parameters to OpenIdConnectConfiguration

[joegoldman2]

Some metadata parameters are missing in OpenIdConnectConfiguration:

• prompt_values_supported from Initiating User Registration via OpenID Connect 1.0
• pushed_authorization_request_endpoint and require_pushed_authorization_requests from OAuth 2.0 Pushed Authorization Requests
• backchannel_authentication_endpoint, backchannel_token_delivery_modes_supported, backchannel_authentication_request_signing_alg_values_supported and backchannel_user_code_parameter_supported from OpenID Connect Client-Initiated Backchannel Authentication Flow
• dpop_signing_alg_values_supported from OAuth 2.0 Demonstrating Proof of Possession (DPoP)
• authorization_response_iss_parameter_supported from OAuth 2.0 Authorization Server Issuer Identification