Add naively higher rate limit for requests with openverse.org referrer

[sarayourfriend]

Problem

We've had to turn off rate limiting due to accidentally rate limiting users in school settings that share a single IP.

Description

These are all from the Openverse.org website. As a temporary holdover until we can create a better solution, we'll just use a separate rate limit class when the referrer header is Openverse.org.

Additional context

We know this is imperfect but there's no good way to solve this right now that doesn't include just leaving rate limiting off entirely for an indefinite period of time. This is a stop gap solution we sould remove once something like #3473 is implemented.