New staged site

[Martin Desruisseaux]

Hello all

Migration to new CMS is slowly progressing. The new staged repository is 
now online, and should be mostly identical to the old one. Below are the 
URL:

 * Site generated by old CMS: http://sis.staging.apache.org/
 * Same site generated by Hugo CMS: https://sis.staged.apache.org/

If there is no comment, I will publish the new site as sis.apache.org 
next week.

    Martin