Update 1.2.0 installers with github actions workflow

[tijcolem]

Pull Request Description

1. Adding a new GitHub workflow that builds the UrbanOpt installers. Currently building Ubuntu arm and x86, Windows and Mac (arm only).
2. Made the windows installers so the gems do not need to be downloaded at runtime. The tool can now be ran in offline mode (no network access). Linux already had this feature.
3. Posted the 1.2.0 installers to the release section.