Code review comment for ~andersson123/autopkgtest-cloud:all-proposed-patch

per Skia's review in a call we're having right now, I'll rename all the variables that use 'env' or something similar, to like additional_params

rabbitmq key will stay as "env"
database column will stay as "env"

e.g.
VARS_FOR_ENV
->
KEYS_FOR_ADDITIONAL_PARAMS