Support for Apple silicon

• Supports Apple silicon natively (and Intel) in one executable
• Looks for Homebrew executable in /usr/local/bin/brew and /opt/Homebrew/bin/brew (but can also be configured)
• Add a Homebrew error menu item if brew services list returns a non-zero exit code.
• Allow a service in error state to be stopped
• New icon in macOs Big Sur visual style (#21)

This is all the work for @stefansundin - thanks! 🙌