Installer M1 Macbook support

[justyntemme]

Darwin_arm64 is missing from the arch detection case switch. /usr/local/bin has migrated to /bin on darwin_arm64 This breaks all installs that try to write to the non existent directory /usr/local/bin, instead of writing to the correct install dir /bin. I would be happy to create a PR with the changes needed if that direction is approved.