This reduces the surface area of our `Kernel` monkeypatch and removes
the need to `include Kernel` in a bunch of modules.
While we're here, also move `Kernel#require?` to `Homebrew` and fully
scope the calls to it.
This should avoid these getting included globally in future.
I found this list from a combination of
https://github.com/Homebrew/brew/pull/17707/files, looking at the
Gemfile and just looking around myself.
Loading different constants can be tricky with all the requires in
Homebrew so we want to strengthen the existing checks to make
sure that things are not getting required when there is a performance
penalty. This expands the existing check to include more constants
beyond `Formula` that we don't expect to be defined and that pull
in a lot of other dependencies.
