Deprecate openID 2.0 support

This commit puts deprecation notice on docs, sample applications and configurations (java and xml)

Fixes gh-7153

docs/articles/src/docbook/codebase-structure.xml

@@ -146,7 +146,7 @@
 								<entry valign="middle">spring-security-openid</entry>
 								<entry>OpenID web authentication support.</entry>
 								<entry>If you need to authenticate users against an external OpenID
-									server.</entry>
+									server. (Deprecated)</entry>
 								<entry><literal>org.springframework.security.openid</literal></entry>
 							</row>
 						</tbody>

docs/manual/src/docs/asciidoc/_includes/about/modules.adoc

@@ -102,6 +102,9 @@ The top-level package is `org.springframework.security.cas`.
 
 [[spring-security-openid]]
 == OpenID -- `spring-security-openid.jar`
+[NOTE]
+The OpenID 1.0 and 2.0 protocols have been deprecated and users are encouraged to migrate to OpenID Connect, which is supported by spring-security-oauth2.
+
 This module contains OpenID web authentication support.
 It is used to authenticate users against an external OpenID server.
 The top-level package is `org.springframework.security.openid`.

docs/manual/src/docs/asciidoc/_includes/servlet/authentication/index.adoc

@@ -33,6 +33,7 @@ This also gives a good idea of the high level flow of authentication and how pie
 * <<servlet-rememberme, Remember Me>> - How to remember a user past session expiration
 * <<servlet-jaas, JAAS Authentication>> - Authenticate with JAAS
 * <<servlet-openid,OpenID>> - OpenID Authentication (not to be confused with OpenID Connect)
+// FIXME: The one above is deprecated. Should it be removed from here as well?
 * <<servlet-preauth>> - Authenticate with an external mechanism such as https://www.siteminder.com/[SiteMinder] or Java EE security but still use Spring Security for authorization and protection against common exploits.
 * <<servlet-x509,X509 Authentication>> - X509 Authentication
 

docs/manual/src/docs/asciidoc/_includes/servlet/authentication/openid.adoc

@@ -1,5 +1,9 @@
 [[servlet-openid]]
 == OpenID Support
+
+[NOTE]
+The OpenID 1.0 and 2.0 protocols have been deprecated and users are encouraged to migrate to OpenID Connect, which is supported by spring-security-oauth2.
+
 The namespace supports https://openid.net/[OpenID] login either instead of, or in addition to normal form-based login, with a simple change:
 
 [source,xml]