Add a table which stores a summary of each user's IP address subnet in
each time bucket, defaulting to 15 days. On edit (and other changes
causing a recentchanges row) and successful login update the table.
On attempted login, check whether the subnet is in the table in any
time bucket back to the expiry time.
Add a job and a maintenance script for purging expired rows.
Disabled by default for now. The idea is to enable it by default after
we have some experience with using it in WMF production.
If CheckUser integration is disabled (the future intended state), the
cache and LoginNotifyChecks job are suppressed since they are
unnecessary.
Details:
* Rename setCurrentAddressAsKnown() to recordKnownWithCookie() and
split off recordKnown() which does the same thing except without
sending the cookie. We use recordKnown() to store the IP address
without sending the cookie, on non-login changes.
* Reorganise isKnownSystemFast() for clarity, and return emphatic
USER_NOT_KNOWN if the user is not in the table, cache or cookie
and CheckUser integration is disabled.
* Replace time() calls with a mockable method.
Bug: T345052
Change-Id: Iea716e660353f16c47f873fe42edc2aeec1b4346
