Create a Welcome screen with instructions

Create an out-of-the-box welcome screen with nice graphics and demonstrations of how it may look like.
Possibly include a small wizard to initialize some important elements in the system like: tags, categories, points, default challenge etc.
This page may also include explanations about the pointing system and how to configure it. It should give the users the confidence they chose the right system

This screen will later be used to reconfigure OpenideaL. See #2161317: Improve admin screen - concentrate everything openideal under a single page (with tabs)