Switch base image from Alpine to Debian

[Nuru]

what

• One way we publish packages is via a Docker image with the packages loaded. That has previously been based on Alpine. This PR changes the base to Debian.
• Install amd64 binaries for CloudFlare commands on Apple Silicon Macs

why

• Alpine has ongoing compatibility issues and Cloud Posse now prefers to use Debian where possible.
• CloudFlare does not publish native arm64 binaries for their commands, but the amd64 ones run on arm64 Macs due to Mac having emulation built into the OS