[SCHEMA CHANGE] Add corresponding *_user_wiki field to all *_user_id fields

This is to distinguish users and ips from different wikis especially
for pages like contributions.

The steps involved:

1. deploy https://gerrit.wikimedia.org/r/#/c/112794/
2. add the columns to production wikis
3. deploy the code in this patch so the new columns start collecting data
4. run maintenance script to populate existing records
5. update cache version key
6. patch to use the new columns

Change-Id: I439b102e9125c4e6aed988032a21d51b1079f93b