Add FireBot to Brew package manager for easier updates on macOS

[LooneyH]

Currently, macOS and Linux both require that new updates be downloaded from Github, where I feel that one way that could help reduce some friction for users would be to add Firebot to popular package managers. I don't know if it is already present on any Linux package managers already, but I know it is not on Brew for macOS.

From what I can tell looking at Brew's requirements in terms of what software is allowed to be added to their repository, Firebot doesn't seem to have any conflicts. I think the last one that was needed was ARM64 support, which it now has. I have been meaning to try adding it myself but I feel it would be better placed for someone with a better understanding of the codebase to know if there may be some conflicts.