impl: retrieve supported response type and the dynamic client registration url

OAuth endpoint `.well-known/oauth-authorization-server` provides metadata about
the endpoint for dynamic client registration and supported response types.
This commit adds support for deserializing these values.

Author: fioan89

src/main/kotlin/com/coder/toolbox/oauth/AuthorizationServer.kt

@@ -7,6 +7,8 @@ import com.squareup.moshi.JsonClass
 data class AuthorizationServer(
     @field:Json(name = "authorization_endpoint") val authorizationEndpoint: String,
     @field:Json(name = "token_endpoint") val tokenEndpoint: String,
+    @field:Json(name = "registration_endpoint") val registrationEndpoint: String,
+    @property:Json(name = "response_types_supported") val supportedResponseTypes: List<String>,
     @property:Json(name = "token_endpoint_auth_methods_supported") val authMethodForTokenEndpoint: List<TokenEndpointAuthMethod>,
 )