Create a full network.LoadBalancer example in pulumi/examples

[thomas11]

This issue could also be filed in pulumi/examples, but here's the Azure Native expertise.

Defining Microsoft.Network Load Balancers is tricky due to the way they are defined in the spec. This comes up repeatedly, e.g., in #3601. The use of $self for sub-resources can help but is sparsely documented.

A comprehensive and well-documented example, defining a load balancer with backend address pools and other supporting components, could help. It would go in pulumi/examples so users can find it. This provider's CI would automatically test it nightly against the latest provider. We could then link it from the LoadBalancer docs.

There are existing examples in our integration test suite. They could serve as a starting point:
py-loadbalancer and py-loadbalancer-subresource.