Follow up on `DownloadQueue` for download concurrency on `brew fetch`
and `brew install` to also add support for `brew reinstall` and
`brew upgrade`.
This required a fair bit of refactoring to make this work so I've also
made `install.rb`, `reinstall.rb` and `upgrade.rb` `typed: strict` to
add some extra guardrails from Sorbet here.
Co-authored-by: Carlo Cabrera <github@carlo.cab>