Build for more platforms

[lucacome]

Proposed changes

Debian builds packages for ppc64 and riscv64. Alpine supports mips64.
NGINX runs on freebsd and solaris.
This PR adds support for all those architectures and platforms.
It also adds docker builds for all variants of arm and riscv64

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING guide
• I have proven my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have ensured the README is up to date
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch on my own fork

[pdabelf5]

If we're building for solaris, is that just x86 or sparc too?

[lucacome]

Solaris is only amd64, this is the list of supported OSes and architectures https://go.dev/doc/install/source#environment