Define oauth2-login xsd elements

Issue gh-4557

docs/manual/src/docs/asciidoc/_includes/servlet/appendix/namespace.adoc

@@ -164,6 +164,7 @@ The default value is true.
 * <<nsa-intercept-url,intercept-url>>
 * <<nsa-jee,jee>>
 * <<nsa-logout,logout>>
+* <<nsa-oauth2-login,oauth2-login>>
 * <<nsa-openid-login,openid-login>>
 * <<nsa-port-mappings,port-mappings>>
 * <<nsa-remember-me,remember-me>>
@@ -879,6 +880,148 @@ Maps a `ForwardAuthenticationSuccessHandler` to `authenticationSuccessHandler` p
 * **authentication-failure-forward-url**
 Maps a `ForwardAuthenticationFailureHandler` to `authenticationFailureHandler` property of `UsernamePasswordAuthenticationFilter`.
 
+
+[[nsa-oauth2-login]]
+==== <oauth2-login>
+The <<oauth2login,OAuth 2.0 Login>> feature configures authentication support using an OAuth 2.0 and/or OpenID Connect 1.0 Provider.
+
+
+[[nsa-oauth2-login-parents]]
+===== Parent Elements of <oauth2-login>
+
+* <<nsa-http,http>>
+
+
+[[nsa-client-registrations]]
+==== <client-registrations>
+A container element for client(s) registered (`ClientRegistration`) with an OAuth 2.0 or OpenID Connect 1.0 Provider.
+
+
+[[nsa-client-registrations-children]]
+===== Child Elements of <client-registrations>
+
+* <<nsa-client-registration,client-registration>>
+* <<nsa-provider,provider>>
+
+
+[[nsa-client-registration]]
+==== <client-registration>
+Represents a client registered (`ClientRegistration`) with an OAuth 2.0 or OpenID Connect 1.0 Provider.
+
+
+[[nsa-client-registration-parents]]
+===== Parent Elements of <client-registration>
+
+* <<nsa-client-registrations,client-registrations>>
+
+
+[[nsa-client-registration-attributes]]
+===== <client-registration> Attributes
+
+
+[[nsa-client-registration-registration-id]]
+* **registration-id**
+The ID that uniquely identifies the `ClientRegistration`.
+
+
+[[nsa-client-registration-client-id]]
+* **client-id**
+The client identifier.
+
+
+[[nsa-client-registration-client-secret]]
+* **client-secret**
+The client secret.
+
+
+[[nsa-client-registration-client-authentication-method]]
+* **client-authentication-method**
+The method used to authenticate the Client with the Provider.
+The supported values are *basic*, *post* and *none* https://tools.ietf.org/html/rfc6749#section-2.1[(public clients)].
+
+
+[[nsa-client-registration-authorization-grant-type]]
+* **authorization-grant-type**
+The OAuth 2.0 Authorization Framework defines four https://tools.ietf.org/html/rfc6749#section-1.3[Authorization Grant] types.
+The supported values are `authorization_code`, `client_credentials`, `password` and `implicit`.
+
+
+[[nsa-client-registration-redirect-uri]]
+* **redirect-uri**
+The client's registered redirect URI that the _Authorization Server_ redirects the end-user's user-agent to after the end-user has authenticated and authorized access to the client.
+
+
+[[nsa-client-registration-scope]]
+* **scope**
+The scope(s) requested by the client during the Authorization Request flow, such as openid, email, or profile.
+
+
+[[nsa-client-registration-client-name]]
+* **client-name**
+A descriptive name used for the client.
+The name may be used in certain scenarios, such as when displaying the name of the client in the auto-generated login page.
+
+[[nsa-client-registration-provider-id]]
+* **provider-id**
+A reference to the associated provider. May reference a `<provider>` element or use one of the common providers (google, github, facebook, okta).
+
+
+[[nsa-provider]]
+==== <provider>
+The configuration information for an OAuth 2.0 or OpenID Connect 1.0 Provider.
+
+
+[[nsa-provider-parents]]
+===== Parent Elements of <provider>
+
+* <<nsa-client-registrations,client-registrations>>
+
+
+[[nsa-provider-attributes]]
+===== <provider> Attributes
+
+
+[[nsa-provider-provider-id]]
+* **provider-id**
+The ID that uniquely identifies the provider.
+
+
+[[nsa-provider-authorization-uri]]
+* **authorization-uri**
+The Authorization Endpoint URI for the Authorization Server.
+
+
+[[nsa-provider-token-uri]]
+* **token-uri**
+The Token Endpoint URI for the Authorization Server.
+
+
+[[nsa-provider-userinfo-uri]]
+* **userinfo-uri**
+The UserInfo Endpoint URI used to access the claims/attributes of the authenticated end-user.
+
+
+[[nsa-provider-userinfo-authentication-method]]
+* **userinfo-authentication-method**
+The authentication method used when sending the access token to the UserInfo Endpoint.
+The supported values are *header*, *form* and *query*.
+
+
+[[nsa-provider-username-attribute-name]]
+* **username-attribute-name**
+The name of the attribute returned in the UserInfo Response that references the Name or Identifier of the end-user.
+
+
+[[nsa-provider-jwkset-uri]]
+* **jwkset-uri**
+The URI used to retrieve the https://tools.ietf.org/html/rfc7517[JSON Web Key (JWK)] Set from the Authorization Server, which contains the cryptographic key(s) used to verify the https://tools.ietf.org/html/rfc7515[JSON Web Signature (JWS)] of the ID Token and optionally the UserInfo Response.
+
+
+[[nsa-provider-issuer-uri]]
+* **issuer-uri**
+The URI used to initially configure a `ClientRegistration` using discovery of an OpenID Connect Provider's https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfig[Configuration endpoint] or an Authorization Server's https://tools.ietf.org/html/rfc8414#section-3[Metadata endpoint].
+
+
 [[nsa-http-basic]]
 ==== <http-basic>
 Adds a `BasicAuthenticationFilter` and `BasicAuthenticationEntryPoint` to the configuration.