Changed readme file in order to display install instructions and prerequisites and to remove references to the full update site (until this specific build output works again).
Changed readme file in order to display install instructions and
prerequisites and to remove references to the full update site (until this
specific build output works again).

ymortier/Capella-Extensions,ymortier/Capella-Extensions,ObeoNetwork/Capella-Extensions,ymortier/Capella-Extensions,ObeoNetwork/Capella-Extensions,ObeoNetwork/Capella-Extensions