nutcracker migration: allow wikidev to (re-)start nutcracker

Grant wikidev group the right to start & restart nutcracker service
and provision symlink for new restart-nutcracker script.

Factored out of I42ee37f14. Submitted on behalf of Giuseppe Lavagetto.

Change-Id: I16107e24de2916a6eea8c063ef37edf6b81feb13