Speed up `brew`

[MikeMcQuaid]

Running brew is slower than it could be. Part of this reason is that we require a bunch of ActiveSupport.

It would be a good project to use brew prof and other profiling tools to reduce the time spent to start a brew process.

See more details for a specific suggestion in https://github.com/Homebrew/brew/issues/10508

[mistydemeo]

I like this one. Given this is relatively open-ended, I'd like to tag this as a 350-hour project.