Document what is needed for ci and packing infrastructure #47

We know we want to do most things in things in GitHub actions for simplicity and overhead, but not everything fits into that mold. Things we know we need to document include:

• package signing via vm or cloudrun or lamba
• vmpooler (maybe) on donated k8s
• GH Action runners in k8s
• vm provisioning runners
• document what ci process is desired for what type of things