Add run args and accept barcelona yml vars

[davidsiaw]

Context

This PR allows the barcelona.yml to specify environment variables for container s started specially using the bcn run command. This will allow specific env vars to be set specifically for humans to operate remote services properly, instead of forcing the human to constantly use the export everytime the user needs to do work on the remote machine.

In this change, we add the ability to set a run_env for each environment in the barcelona yml file that only gets passed in when bcn run is used

This also adds a parameter -E to add/overwrite parameters from the barcelona.yml.

Refs #14

1. Create a barcelona.yml with the following:

environments:
  hello:
    name: hello
    image_name: hello_world
    scheduled_tasks: []
    run_env:
      vars:
        ABCDEF: ghi
        HELLO: meow
    services:
      - name: web
        service_type: web
        memory: 256

2. Run this command: bcn -d run -e hello -E HELLO=XD sh
3. Observe the output contains:

{"command":"sh","env_vars":{"ABCDEF":"ghi","HELLO":"XD"},"interactive":true}

[degicat]

@essa please review this

[davidsiaw]

A PR to barcelona will follow to complete this change

[degicat]

@Yuuki77 please review this

[essa]

LGTM 👍

[Yuuki77]

LGTM 👍