feat(docker): Allow multiple instances of scram to run locally (WIP)

[crankynetman]

Runs multiple instances of SCRAM (and associated services) locally using a shared postgres instance, similar to how one would run more than one SCRAM instance in prod. We are not using docker replicas the normal way since that doesn't really work well for running 2 separate instances of the same application (different env vars, etc).

[github-actions]

File	Coverage
All files	81%	✅
config/consumers.py	78%	✅
config/urls.py	69%	✅
config/settings/base.py	69%	✅
config/settings/local.py	72%	✅
scram/route_manager/admin.py	71%	✅
scram/route_manager/models.py	70%	✅
scram/route_manager/views.py	86%	✅
scram/route_manager/api/serializers.py	92%	✅
scram/route_manager/api/views.py	74%	✅
scram/shared/shared_code.py	56%	✅
scram/templates/403.html	91%	✅
scram/templates/404.html	91%	✅
scram/templates/base.html	99%	✅
scram/templates/route_manager/home.html	80%	✅

Minimum allowed coverage is 50%

Generated by 🐒 cobertura-action against 0b0fd32

[samoehlert]

Gonna be good to be able to test syncing locally!