Java version of simple-frontends-with-javalin-and-vue

**Describe the feature**
I would like to request Java versions of this guide:

https://javalin.io/tutorials/simple-frontends-with-javalin-and-vue

**Additional context**
Additionally, I would like to suggest using ApiBuilder.get and ApiBuilder.path to show static method calls in the guides.

The documentation for this page is slightly incorrect for the new Javalin. According to error logs as of Javalin 4 we use:

path("{userId}", () -> {

instead of

path(":userId", () -> {