feat: extract client auth code in a library

packages/java/hilla-react/src/main/java/dev/hilla/HillaReactAuth.java

@@ -0,0 +1,10 @@
+package dev.hilla;
+
+import com.vaadin.flow.component.dependency.NpmPackage;
+
+/**
+ * Empty class that adds <code>@hilla/react-auth</code> npm package dependency.
+ */
+@NpmPackage(value = "@hilla/react-auth", version = "2.2.0-beta1")
+public class HillaReactAuth {
+}