Make quick + hacky scheduler in Egglog that implements node limit

[ninehusky]

We can get started using this PR from Yihong. As the e-graph grows to a larger size, one of the bottlenecks will begin to be that we can't fully apply rules; maybe we only want to apply expensive rules until a certain node limit. I'm unsure if this will get merged; if it does we should use it, but if it doesn't the impression I got from the team is that implementing this myself won't be too hard.

[ninehusky]

^ let's also not work on this until it becomes a problem; right now other optimizations are more important.