Benchmarking Utility Functionality

[willtebbutt]

At present, while I know what code it is that you should benchmark / profile to understand Mooncake's performance on a particular function of interest, this functionality isn't exposed to users. There's a small amount of boilerplate code required to construct the code that should be benchmarked / profiled, so we should add one or two user-facing functions which handle this boilerplate for you, and declare "the things I return are the things you should call @benchmark / @chairmark on", and "the things I return are what you should profile".