Update workflows to use Dockerfile

[PaulZC]

This PR:

• Updates the workflows so they use the Dockerfile for compilation
  • All the arduino-cli code is now in a single file
  • TODO: find a better way to keep the GitHub secrets secret
  • The GitHub secrets are passed to the Dockerfile as ARGs
  • The docker build is quiet, output is suppressed to prevent echoing the secrets to the console
  • Docker has other formal ways of handling secrets, but - at the moment - I can't figure out how to: pass the secrets into the docker build, and keep the secrets secret when they are passed to the Dockerfile and are added to the arduino-cli compile call as string params