benchmark with Agents.jl

[kris-brown]

Compare runtime / memory for executing various rewriting recipes to the analogous programs constructible with https://juliadynamics.github.io/Agents.jl/stable/

[kris-brown]

A crude benchmark is there - but I'll leave this issue up as a reminder for me to adapt more examples from Agents.jl docs as well as try to encode some examples using Agents.jl that are quite natural for AlgebraicRewriting (but unnatural for Agents.jl)