Containerize load balancer

### Context?
The way you would use the load balancer right now:
- Run the backend services using `docker-compose up` - This runs your services in docker containers managed by compose.
- Run load balancer using the binary (`./docker-lb`) - This runs the load balancer as a process in your system (outside containers)

### What's wrong with this?
- It would make more sense to run the load balancer in a container as well.

### So what changes can be done?
- Create a docker image for the LB.
- Figure out how networking would work - since we're running the lb in a different network namespace than that of host (container) now.
- Restructure demo services accordingly.

### Note
Comment below if you'd like to work on this issue to indicate your interest and let us know so that we can assign you! :smile: