Added VSCode debugging (for MvcSandbox) & code analysis support (#29486)

* Added VSCode debugging support for MvcSandbox

* Added ignored vscode folders

* 1. Convered some more projects.
2. Added env variable for TargetFramework and used it in launch.json file rather than
hardcoding TFW.

* Addressed PR feedback.
1. Removed extensions.json
2. Updated BuildFromSource.md for Vscode instructions.
3. Added launch settings for BasicTestApp.

* Addressed PR feedback!