Support VSCode extensions

[JHarrisGTI]

Is your feature request related to a problem? Please describe.

VSCode's Jest extension is a tremendously useful tool when developing Angular apps. It lists your tests in VSCode's Testing sidebar, auto-runs tests when your code changes, and lets you easily run or debug specific tests.

I have not been able to get any Jest-related VSCode extensions working in my projects or in the examples/angular folder you provide. This makes me sad.

Describe the solution you'd like

I'd love it if there was a way to use VSCode's testing panel with jest-preview. Using the official Jest extension would be great, but honestly I'm not picky.

Describe how should jest-preview implements this feature

We just need to be able to pass command-line arguments to Jest. In my projects, ng test works correctly, but when I run Jest directly, it chokes on the CSS. This is unfortunate, because as far as I can tell, ng test doesn't accept all the same command-line arguments that jest does, and extensions rely on those command-line arguments to do things like listing the tests to be run. If I knew the command to make Jest run the same way that ng test makes it run, I'm pretty sure I could get the extension working.

Alternatively, if I knew a way to get ng test to pass command-line arguments to jest, that would also fix the issue.