* feat (JAVA SPRING RESTTEMPLATE) 17571: initial commit for Spring RestClient
* feat (JAVA SPRING RESTTEMPLATE) 17571: Copied and changed the webclient mustache files
The RestClient API is oriented on the WebClient API so many parts of the templates can be the same
* fix (JAVA SPRING RESTTEMPLATE) 17571: Renaming error & add README template
The README must be changed because the minimal Java Version for this client is 17
* fix (JAVA SPRING RESTTEMPLATE) 17571: Imports, compile errors and cookie setting
* feat (JAVA SPRING RESTTEMPLATE) 17571: Add generated samples
* test (JAVA SPRING RESTTEMPLATE) 17571: Add tests
* feat (JAVA SPRING RESTTEMPLATE) 17571: Update doc
* Add the restcilent to samples-java-client-jdk17.yam
The minimum Java version of the used Spring Version is 17
* fix (JAVA SPRING RESTTEMPLATE) 17571: Workflow paths to petstore samples
* fix (JAVA SPRING RESTTEMPLATE) 17571: Regenerated samples
* feat (JAVA SPRING RESTTEMPLATE) 17571: Generated echo-api sample for RestClient
* fix (JAVA SPRING RESTTEMPLATE) 17571: Missing import
* fix (JAVA SPRING RESTTEMPLATE) 17571: Missing body class exception when null body is set
* test (JAVA SPRING RESTTEMPLATE) 17571: Add echo-api Auth test
* fix (JAVA SPRING RESTTEMPLATE) 17571: Gradlew file permissions
* feat (JAVA SPRING RESTTEMPLATE) 17571: Reggenerate samples after rebase
* test (JAVA SPRING RESTTEMPLATE) 17571: Add echo-api Body gif test
* test (JAVA SPRING RESTTEMPLATE) 17571: Add echo-api octet stream body test
* test (JAVA SPRING RESTTEMPLATE) 17571: Add echo-api multipart form data test
* fix (JAVA SPRING RESTTEMPLATE) 17571: Form as body when body is null
Also regenerated the restclient samples
