Provide options to disable telemetry, and add telemetry/data collection notice

[victorhuangwq]

Telemetry Notice. If the release has code that enables Microsoft to collect telemetry, also include in the repository:

• instructions to turn off the telemetry;
• this telemetry/data collection notice in a the README.md file.

[david-risney]

There is no explicit telemetry to disable. We do network request for the WebView2 announcements.