App: show a banner on startup, no compilation warning

Really useful to spot when the JVM started when going through service logs.

Actual look:

          _
     _ __| |___  __ _
    | '_ \ / _ \/ _` |
    | .__/_\___/\__, |
    |_|         |___/
    04/03 04:11:08 [main] INFO  Started with config [...]