by default the public alert page is cached 300s, but that can be changed
with an environment variable when deployed

to avoid confusion, dqr link now only appears when dqr_request label is applied

the 'django.requests' logger only has an 'mail_admins' handler, so
we can safely remove this block of code and still have the 429's hit
the actual logs.

superevent_neighbours was not included in igwn-alerts due to a
bug in the previous commit. discovered after testing on playground. ex:
https://ligo-caltech.sentry.io/issues/4264227248/?project=1425216

https://chat.ligo.org/ligo/pl/4obc7ofdkffqfm3obidgdij3qc

This reverts commit ef1026e4.

show each event in a superevent, when it was uploaded, when it was
added to a superevent, and when it was made preferred.