* renaming developer doc to contributor doc
* flattening contributor doc to ease reading the whole content in a shot
* rewrite devstack documentation
* adding Axel and myself as maintainers
Signed-off-by: Arnaud Morin <arnaud.morin@ovhcloud.com>
Change-Id: If25d342c7cc2568b2d86c88bf6a049522559bf50
e75b6b356f