Bug 1053940 - docker-worker: Encrypted environment variables

One open issue is the management of the gpg keys. Currently they are hard-coded.
Hmm... Mostly I use lodash for `_.defaults` to provide default options... `_.forIn` to iterate over dictionaries, and  `_.without` to remove elements from arrays.

I do use `indexOf`, `forEach` and `map` on array... but I will not dispute that using `_.contains` reads better than `.indexOf(..) !== -1` :)

Anyways, that is just what I do...