Improve multi-root CMake detection

[gcampbell-msft]

Brief Issue Summary

Related open issues: #2338, #1069.
Related closed issues: #3278, #3170.

Scenario

In a multi-root workspace, people are hitting issues where, when some of the roots are CMake, and some are not, the CMake extension is attempting to activate and do work for all of the roots, despite some not being CMake.

This includes attempting to add the root to the Testing support, attempting to configure intellisense for it, etc.

Possible Solutions

We believe the best way to solve this is to fix the design around how we detect and integrate with multi-root support. We should better detect at a root level whether each folder is itself a CMake project and then handle that accordingly for the various things that we provide with the extension (i.e. Test integration, configuring, etc.)

We want to be able to correctly detect this so that we can ensure that the CMake Tools extension is inactive for folders that aren't CMake projects.

CMake Tools Diagnostics

No response

Debug Log

No response

Additional Information

No response