Bug 1053940 - docker-worker: Encrypted environment variables

One open issue is the management of the gpg keys. Currently they are hard-coded.
Would it be cleaner by doing similar to what travis does:

task: {
  payload: {
     image: "...",
     env: {
       "secure": <cipher text>,
       "secure": <cipher text>,
       "DISPLAY": 0,
       "PATH": "/usr/bin"
     }
  }
}  

this way you don't have to come up with unique names for each secure env variable you want to add like above with "SEC_VAR1", "SEC_VAR2".