add Erik to statistics-privatedata-users,researchers

RT #8826 asked for access to stat1002/stat1003
and these groups:

(stat1003 - statistics-users group)
(stat1003 - researchers group)
(stat1002 - statistics-privatedata-users group)
(stat1002 - analytics-privatedata-users group)

some of them were already done, just adding the missing 2 here

Erik has had this approved by his manager Erik.

Change-Id: I2dd12d48eaf519ffa2c9d84beeeee532316840cd
RT: 8826