Ingress support for major cloud providers

[mrsabath]

Ingress support provided by #68 is a great addition to our deployment charts.

The next step is to provide easy to follow instructions on setting up the Ingress in various Clouds for the major cloud providers. There is currently a different process for setting up correctly the ingress in different clouds. This is especially challenging to support TLS and mTLS services.

I think it would be a good idea to document the step-by-step instructions how to setup SPIRE (and all the related services) to have public ingress access for various cloud providers deployments. This could be done in form of a github documentation, quickstart, example, or a blog.