chore: move the go code into a subfolder

apps/api/internal/integration/sink/stub.go

@@ -0,0 +1,11 @@
+//go:build !integration
+
+package sink
+
+import "github.com/zitadel/zitadel/internal/command"
+
+// StartServer and its returned close function are a no-op
+// when the `integration` build tag is disabled.
+func StartServer(cmd *command.Commands) (close func()) {
+	return func() {}
+}