Add a load balancer to handle multiple sites, standard web ports

Problem/Motivation

DDev automatically spins up a load balancer to facilitate running multiple sites simultaneously. It also runs on standard ports - 80 and 443.

Drupal Flake avoids this problem by using a different port for each project -- you can run multiple projects at once, as long as you specify a different port for each. Nginx then can attach to that port and correctly route traffic.

So this isn't a high priority at the moment, because you can easily accomplish the same goal -- and as long as you specify a port higher than 1024, you don't need root to run Drupal Flake, if you have Nix installed.

Proposed resolution

If you want to use standard web ports, you somehow need to grant permission to do this.

If you want to run multiple projects through the same port, you need a proxy to do this -- and a way for each project to register their configuration with the proxy.

This could be a different build, run-target, and/or dev shell that we could add to the Drupal Flake -- but would need to make some further decisions on how to do this.

If this is something you want, please add a comment and describe your scenario!

Remaining tasks

1. Identify whether or not there's a need to do this

2. Identify an approach to make it work

3. Implement the approach.