Make java spring controller constructor public. (#4972)

* Make java spring controller constructor public.

This lets users manually create the controller and inject the delegate in the
spring configuration file, instead of letting spring scan for controllers and
autowire the delegate.

* Ran spring-all-pestore.sh.

modules/swagger-codegen/src/main/resources/JavaSpring/apiController.mustache

@@ -33,7 +33,7 @@ public class {{classname}}Controller implements {{classname}} {
     private final {{classname}}Delegate delegate;
 
     @org.springframework.beans.factory.annotation.Autowired
-    {{classname}}Controller({{classname}}Delegate delegate) {
+    public {{classname}}Controller({{classname}}Delegate delegate) {
         this.delegate = delegate;
     }{{/isDelegate}}