SimpleUI: add oauth2 support (#2400)

* simple-ui: add oauth2 support

This uses a trick to ensure that the id token is refreshed; it needs to be revisited after Spring Security 6.5 is released

* fixed style and added a way to enable / disable oauth2 client

hawkbit-simple-ui/pom.xml

@@ -81,6 +81,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-security</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-oauth2-client</artifactId>
+        </dependency>
     </dependencies>
 
     <build>