License copyright eligible files under BSD-2-Clause

Most files in this repository carry a license header explaining
the work is trivial and doesn't meet requirements for copyright
under civil law juridictions like Belgium, France, Germany.

When a code or config file is merely mechanical, generic or when
the content is inevitable according the infrastructure constraint,
there is no "empreinte de la personnalité de l'auteur" / Schöpfungshöhe.

Now, some of the files have initially been asserted below the threshold
of originality but evolved with complex design decisions or creative
problem-solving approaches. As such, they qualify for copyright.

License is the usual BSD-2-Clause license.

Detailed rationale in P399.

Differential Revision: https://devcentral.nasqueron.org/D4045