Remove "no cdn" concept from install script.

[richlander]

This is an anti-pattern.

install-scripts/src/dotnet-install.sh

Lines 1408 to 1412 in 33dc34f

	if [[ "$no_cdn" == "true" ]]; then
	feeds=(
	"https://dotnetcli.blob.core.windows.net/dotnet"
	"https://dotnetbuilds.blob.core.windows.net/public"
	)

[baronfel]

I'm slightly concerned about removing functionality here, but I do not see much usage in public at all. Most of the usage seems to be from a thing called "ray-dotnet-install.sh". I think we can cut it, though.

[baronfel]

@JanProvaznik this one as well :)

[richlander]

Even if people are using it, it isn't something we should be offering or encouraging.