Add ability for ContainerResource to reach ProjectResource by name in Run mode

[dombrovsky]

This modifies Metrics sample.

The goal is to change in prometheus.yml this
- targets: ['host.docker.internal:5048'] # hard-coded port matches launchSettings.json
to this
- targets: ['app'],
so that prometheus container can reach metricsapp that runs on host in development environment by resource name instead of hardcoded endpoint.

In this PR this is achieved by:

1. Creating custom docker network and adding all ContainerResource to it.
2. Adding simple Nginx container with network alias equal to ProjectResource name which should be accessible by container.

[davidfowl]

I don't think we should make the metrics example more complex.

[davidfowl]

This container proxy resource is a very cool stand alone sample though.

[dombrovsky]

Thanks for review. I'll prepare it as a standalone sample and update PR.