java-openliberty:  In template(s) use property to reference app name from server.xml config

Instead of:

 ```
 <webApplication location="starter-app.war" contextRoot="/"/>
```

in **templates/default/src/main/liberty/config/server.xml** we should be referencing the artifactId or the finalName which is I think what the MP starter does:  (https://github.com/eclipse/microprofile-starter)