Test @types/vscode and vscode-test

[octref]

Test for #71048

• Mac @Tyriar
• Linux @aeschli
• Windows @bpasero

Complexity: 2

Overview: vscode has been split into @types/vscode and vscode-test. See the reasoning here: microsoft/vscode-extension-vscode#147

Release notes | Docs

Please test:

• run npm install -g generator-code@next
  This should install generator-code@1.2.0-next.0
• yo code with TS/JS generates an extension with @types/vscode and with integration tests setup using vscode-test
• You can run the integration test (yarn test or running it from debug target) in https://github.com/microsoft/vscode-extension-samples/tree/master/helloworld-test-sample
• You can modify the test script and test runner following the documentation
• You can easily understand the purpose and usage of https://github.com/microsoft/vscode-dts (
• vsce prevents you from publishing an extension when you have @types/vscode > engines.vscode in package.json.

[bpasero]

I skiped over the "VSCE" part.

[aeschli]

Documentation link does not work for me

[octref]

Fixed link

[octref]

I thought it's mostly going to be small changes, but the API parts need some discussion which I don't have bandwidth for. I pulled it out from release notes and will continue in June. Thanks for testing!

[aeschli]

Created branch https://github.com/microsoft/vscode-generator-code/tree/vscode-test-and-types-at-code with all the commits.
Set master back to the previous version to avoid that the changes get pushed inadvertently