GH-267 - Explicitly declared empty allowed dependencies now forbids any dependency.

The default for @ApplicationModule(allowedDependencies) is now a single element list with a dedicated token we recognize as "all dependencies allowed". This allows users to declare an empty array explicitly to disallow any outgoing dependencies for an application module. Previously, such a declaration would have allowed any dependency.

spring-modulith-integration-test/src/main/java/example/declared/second/package-info.java

@@ -0,0 +1,3 @@
+// No explicit allowed dependencies -> all allowed
+@org.springframework.modulith.ApplicationModule(displayName = "Second")
+package example.declared.second;