Add Bool module

[fhammerschmidt]

As those methods will be removed from pervasives.
Also added some helpers inspired from https://hexdocs.pm/gleam_stdlib/gleam/bool.html

Please tell me which ones you would like to keep, then I will add tests and docs.

[bloodyowl]

I'm wondering if we really need such a module in the stdlib, I'd rather encourage using plain expressions (inside anonymous functions if needed)

[fhammerschmidt]

Probably not. It was mainly to have a substitute for the corresponding Pervasives methods, but we also have this now: https://github.com/rescript-lang/rescript/blob/master/runtime/Primitive_bool.res