Install the qos apache module
When geyeri, serving donate.tpo, got hammered in December last year, we added the qos module to its apache2 and configured it to allow for at most 11 or so simultaneous connections from a single source IP address. This saved donate.tpo, at the price of possibly making the site unusable for some people behind the same IP address.
We should do that for the host serving trac and see if it helps with the sad trac situation when we're being crawled.
cf https://trac.torproject.org/projects/tor/wiki/org/meetings/2019BrusselsAdminTeamMinutes#Trac