add test notarize command

[willmurphyscode]

Fixes #617

Some implementation notes:

1. This works by embedding the contents of a "hello world" program built by go into the quill binary. Quill writes it to a temp file and then hands its path off to the production sign and notarize code paths.
2. This commits the macho file (without the execute bit set, because we don't need that) that will be test notarized. Otherwise, the go embed instruction fails during go install
3. See the linked issue for why we need this.