preliminary_checks must be standard job from a standard stage, not a builtin one, so that the trick with notest- branches for merge request works

PRUVOST Florent authored 6 years ago and Mathieu Faverge committed 6 years ago

    improve user's doc style
    add some explanation about the code structure in the main doxygen
    fix coverage in analysis sonarqube
    add a release job to automatize release publication
    change the cdash server to my.cdash.org which is more recent and reactive than cdash.inria.fr
    fix the version number, dates and authors in headers to prepare the release 0.9.2