Merge pull request #12491 from denisw:oauth2-server-docs

* pr/12491:
  Add OAuth2 server implementation section to docs

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -3193,6 +3193,17 @@ In other words, the two configurations in the following example use the Google p
 
 
 
+[[boot-features-security-oauth2-server]]
+==== Server
+Currently, Spring Security does not provide support for implementing an OAuth 2.0
+Authorization Server or Resource Server. However, this functionality is available from
+the https://projects.spring.io/spring-security-oauth/[Spring Security OAuth] project,
+which will eventually be superseded by Spring Security completely. Until then, you can
+use the `spring-security-oauth2-autoconfigure` module to easily set up an OAuth 2.0 server;
+see its https://docs.spring.io/spring-security-oauth2-boot[documentation] for instructions.
+
+
+
 [[boot-features-security-actuator]]
 === Actuator Security
 For security purposes, all actuators other than `/health` and `/info` are disabled by