Remove old SIDEBAR files

SIDEBAR.ftl.md

-## Related resources
-
-Spring Boot provides a wide range of support for various services, including most services documented in the Spring Getting Started guides. Some of these guides are listed here.
-
-### Getting Started guides
-
-* [Building a RESTful Web Service with Spring Boot Actuator][gs-actuator-service]
-* [Accessing Data with JPA][gs-accessing-data-jpa]
-* [Creating Asynchronous Methods][gs-async-method]
-* [Creating a Batch Service][gs-batch-processing]
-* [Securing a Web Application][gs-securing-web]
-* [Uploading Files][gs-uploading-files]
-* [Converting a Spring Boot JAR Application to a WAR][gs-convert-jar-to-war]
-
-[gs-actuator-service]: /guides/gs/actuator-service
-[gs-accessing-data-jpa]: /guides/gs/accessing-data-jpa
-[gs-async-method]: /guides/gs/async-method
-[gs-batch-processing]: /guides/gs/batch-processing
-[gs-securing-web]: /guides/gs/securing-web
-[gs-uploading-files]: /guides/gs/uploading-files
-[gs-convert-jar-to-war]: /guides/gs/convert-jar-to-war
-
-### Tutorials
-
-* [Designing and Implementing RESTful Web Services with Spring][tut-rest]
-* [Designing and Implementing a Web Application with Spring][tut-web]
-
-[tut-rest]: /guides/tutorials/rest
-[tut-web]: /guides/tutorials/web
-
-### Concepts and technologies
-
-* [REST][u-rest]
-* [JSON][u-json]
-
-<@u_rest/>
-<@u_json/>

SIDEBAR.md

-## Related resources
-
-Spring Boot provides a wide range of support for various services, including most services documented in the Spring Getting Started guides. Some of these guides are listed here.
-
-### Getting Started guides
-
-* [Building a RESTful Web Service with Spring Boot Actuator][gs-actuator-service]
-* [Accessing Data with JPA][gs-accessing-data-jpa]
-* [Creating Asynchronous Methods][gs-async-method]
-* [Creating a Batch Service][gs-batch-processing]
-* [Securing a Web Application][gs-securing-web]
-* [Uploading Files][gs-uploading-files]
-* [Converting a Spring Boot JAR Application to a WAR][gs-convert-jar-to-war]
-
-[gs-actuator-service]: /guides/gs/actuator-service
-[gs-accessing-data-jpa]: /guides/gs/accessing-data-jpa
-[gs-async-method]: /guides/gs/async-method
-[gs-batch-processing]: /guides/gs/batch-processing
-[gs-securing-web]: /guides/gs/securing-web
-[gs-uploading-files]: /guides/gs/uploading-files
-[gs-convert-jar-to-war]: /guides/gs/convert-jar-to-war
-
-### Tutorials
-
-* [Designing and Implementing RESTful Web Services with Spring][tut-rest]
-* [Designing and Implementing a Web Application with Spring][tut-web]
-
-[tut-rest]: /guides/tutorials/rest
-[tut-web]: /guides/tutorials/web
-
-### Concepts and technologies
-
-* [REST][u-rest]
-* [JSON][u-json]
-
-[u-rest]: /understanding/REST
-[u-json]: /understanding/JSON