Use env vars in Docker compose and swarm mode (#20)

- deployment seems stable
- reverting to fewer containers for review branches
- add placement constraints
- update CODEOWNERS
- app is buildable (a) locally, (b) using docker-compose, and (c) with docker-swarm.
- split .env into local, compose, and stack
- add support for multiple brokers in swarm mode
- persist rabbitmq data in compose mode
- add secrets and configs in compose mode
- update CD steps to expose and scale brokers, workers using Space UI
- fix a bug where NumWorkers was force-set to 1.
- increase healthcheck start interval to 5min for very slow hosts in swarm mode
- remove unusable test, include a stub test
- include a deployment config for swarm mode
- expose env vars to stack, compose, and local dev environment
- update CD pipeline to use new configs
- add health-checks in compose
- cleanup stack file
- remove unused env vars
- expose RMQ runtime params as env vars
- read and use env vars as config, with fallback
- refactor microservices to not use hardcoded paths
- remove unneed files
- gracefully handle exposing and using JWT secrets as env vars or secret file
- added a stress test file for the microservice.

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Co-authored-by: Hasibul H Rasheeq <hrashee@ncsu.edu>