[Feature request] Provide ability to build CLI with telemetry removed or disabled by default

[4creators]

One of the requirements of many distros as indicated in one of the comments in .NET core should not SPY on users by default issue is an ability to build CLI with telemetry disabled.

As this is a fundamental requirement for many applications dotnet support for that configuration knob would be very helpful for oss community and teams / projects working with legally protected or otherwise sensitive data (it is my use case).

This request is related to issue #187

[dseefeld]

Distros are free to patch telemetry out of the product.

[omajid]

Here's the fix we are looking at using in Fedora with source-build to disable telemetry by default: https://pagure.io/dotnet-sig/dotnet-2-1/pull-request/9#request_diff