CI: Add Benchmarking

[Jacob-Stevens-Haas]

Hey Andy, I've added some logging to an experiment and found that some derivative methods can be slow. This isn't a surprise, but the enterprise solution is to add benchmarking to CI so that we can start quantifying improvements. This uses Airspeed Velocity (asv), the same benchmarking package as pandas.

Like most PRs that deal with CI, this one may have a variety of commits to try to get it working. I don't know yet how to feed asv previous benchmark results so that it can know performance improvements/regressions.

[Jacob-Stevens-Haas]

Ok, it looks like the basic benchmarking is working. You can see that the commit with an intentional performance regression failed CI.

Two things I'd like to add:

• test memory useage for finite difference

• asv publish artifact so that it's possible to browse the results of the benchmarking action (It'll look like pandas, but with only the merge-base and PR as the two commits) This'll have to wait for a later PR if it's desired.

I'd like to just leave this with a test for finite difference as a template later expansion and improvement. I think the PR is ready to go now

[andgoldschmidt]

This is great, and will hopefully encourage contributions.