Detect and prompt if launched from MSStore

[SteveL-MSFT]

Summary of the new feature / enhancement

Currently, not able to get it certified in the MSStore because the test requires after install clicking the Open button in the MSStore and expecting to see something. Since dsc.exe doesn't get mandatory params, it will show help and quickly exit.

Proposed technical implementation details (optional)

I think a solution would be on Windows, see if the parent process is explorer.exe or WinStore.App and instead of showing help (so before args are parsed), show text that this is a command-line tool and should be used from the console and prompt before exiting. Also include aka.ms link to help docs.

[SteveL-MSFT]

Fixed via #481