remove the need for separate <stack>_name.env file

cache/Dockerfile

cache/run-seeder.sh

chart/values.yaml

core/Dockerfile

docker-compose.dem.yml

docker-compose.emg.yml

docker-compose.vhr18.yml

documentation/operator-guide/configuration.rst

env/dem_redis.env

env/emg_redis.env

env/vhr18_redis.env

ingestor/Dockerfile

preprocessor/Dockerfile