Add formulae to homebrew

[mmadson]

Allow cli to be installed using brew.

[mmadson]

Looks like as the primary authors we are not able to submit this to homebrew directly, given their policy:

https://docs.brew.sh/Acceptable-Formulae#niche-or-self-submitted-stuff

So if enough people find the cli useful, a contributor is more than welcome to submit the formulae to homebrew on our behalf. Please reach out to me and I can help setup the formulae if anyone is interested.

Alternatively we can create our own homebrew tap to host the formulae, will create an issue for creating a tap.

[mmadson]

Example forumale that we can use as inspiration:

https://github.com/Homebrew/homebrew-core/blob/9b4fd1f2b0a37be1609d23e078d3bc1db50b099b/Formula/swagger-codegen.rb