Missing documentation about the ALE examples

[dvojtise]

Official examples are provided with some documentation explaining how they work and how they differ from other approaches (K3 vs Moccml vs ALE vs other engines)

The ALe examples should be documented too.

Ideally, it should follow the previous schema:

• available both in help and in web,
• propose a DIY section explaining how to recreate from scratch a similar example

This is required if we wish that ALE replaces k3 as preferred/flagship action language for GEMOC
(see https://download.eclipse.org/gemoc/docs/nightly/K3FSM-example.html and https://download.eclipse.org/gemoc/docs/nightly/K3FSM-example.html#K3FSM-example-DIY