Try to improve the installation guide (#7757)
Try to improve the installation guide (#7757)

* move generic instructions to the beginning of the file
* add an example of ingress resource creation
* simplify a few commands to make them shorter and simpler
* add short paragraphs about PROXY protocol and traffic policy

This tries to address the concerns I expressed in #7701.
canhnt/ingress,kubernetes/ingress-nginx,kubernetes/ingress-nginx,kubernetes/ingress-nginx,canhnt/ingress,canhnt/ingress,canhnt/ingress,kubernetes/ingress-nginx,kubernetes/ingress-nginx