Implement Smarter Rate Limiter

[zoffixznet]

Currently we use a static rate limiter that just sleeps for 3 seconds 1 second between fetching dists. There's actually a GitHub API endpoint the builder script can access to see how many requests we still have available and then calculate the rate limit based on that.

In the end, I think this will let it update the site more often, as we'll scale the rate limit to the actual number of dists we have.

[timo]

i'd say what we've implemented recently covers this. the updater now does the github requests at "full speed" most of the time.