Celery broker url broken for non-Docker

[Ed McDonagh]

settings.py has the celery broker URL as BROKER_URL = "amqp://guest:guest@broker:5672//" whereas for non-Docker Linux install needs it to be BROKER_URL = "amqp://guest:guest@localhost:5672//"

[Ed McDonagh]

Created BROKER_URL variable. Refs #849

→ <<cset 17169c9603bb>>

[Ed McDonagh]

Added ref #849 to changes. Tested locally.

→ <<cset 4d528e722ed6>>

[Ed McDonagh]

Merged in issue849brokerURL (pull request #384)

Fixes #849

→ <<cset 3d4169c5b427>>