Doc: Hide license from "Getting Started" snippets

There's no point showing 5 copies of the license text on 1 page. It just
adds noise with no benefit to the reader.

Furthermore, a few of these snippets are described in the tutorial as
being auto-generated by the Qt Creator wizard; the wizard would not
generate the license text.

Change-Id: Ifddd1238eb815ce86db7ebb0dabab08f5b547dbc
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>