user tracking cookie scheme needs deployment

[samuel-archive]

the other day we figured out a sane scheme for doing user tracking on www.a.o:

issue users a longlived cookie 'archive-user-tracking' with a nonce as a value

log that cookie with requests at apache level
have log-hide-ip.pl apply the same ip hiding logic it applies to ip #s to the cookie value
put the randomized user cookie in the log file on disk

if we use a global daily rotated key, than we can do sitewide user deduping, and get a count of
browser visits per day

to do this we need:
cookie setting logic
enhanced log-hide-ip.pl to handle cookie fields
apache config that logs user cookies
deployment of key rotation scheme