Consider adding error rate-limiting to Steamclog

[jacobminer]

Given that most (all?) our projects use Sentry now, it might be beneficial to add some logging-level rate-limiting for fatal and non-fatal errors. On apps with a large user-base, it's easy to burn through our Sentry allocations with one bug, but we could improve this situation a lot by limiting the number of times a single client can send the same error within a period of time (a session, a day, etc).