Add initial Dockerfile
Skip "test-fs-readfile-pipe" in the Dockerfile for now since it relies on "/dev/stdin" which the index's current version of Docker doesn't create (so our Trusted Build fails)
Switch Dockerfile to use buildpack-deps as the base and add TODOs for ONBUILDs
Dockerfile: remove gcc deps

As it is included in the base image (through build-essential)
Dockerfile: skip test-http-pipeline-flood
Dockerfile: skip test-debugger-client
Update Dockerfile to use unprefixed buildpack-deps image