packaging: Homebrew

[timoguin]

Add the ability to install from Homebrew. Create a tap and and Cask Formula to install
the binary (don't bother a regular formula that installs from source).

References

• https://docs.brew.sh/How-to-Create-and-Maintain-a-Tap
• https://docs.brew.sh/Taps
• https://github.com/Homebrew/homebrew-cask/blob/master/doc/development/adding_a_cask.md
• https://vanwollingen.nl/distributing-private-tools-through-homebrew-d046761fb3a1