driver: firecracker

[bradrydzewski]

support firecracker as the runtime engine. The corresponding yaml would be slightly different than docker, and would look something like this:

---
version: 1
kind: pipeline
type: firecracker

settings:
  image: debian.img

platform:
  os: linux
  arch: amd64

steps:
- name: build
  commands:
  - go build
  - go test