Take ownership of the default node, chrome, extensionHost, and msedge types

[connor4312]

This month we are (finally) removing the legacy Node debug extensions from being built-in. All old debug extensions will still be accessible in the marketplace, but they (including the Chrome and Edge debuggers) will require the legacy- prefix in the launch "type" to use. The debug.javascript.usePreview setting is going away.

js-debug will take ownership of the default launch types, and will no longer require the pwa- prefix. However, we will continue allowing the "pwa-" prefix in launch.json's and the "redirection" logic will ensure launched sessions are prefixed, to avoid breaking extensions that depend on the type.

[bpasero]

Steps?

[connor4312]

1. Create a launch config using each of the listed types
2. Set trace: true in the config
3. Verify that the path logged in the Debug Console ends with .json.gz (easiest indicator of the new debugger)
4. Do the same with types using a pwa- prefix, and verify that it still works

[weinand]

I've verifed:

• setting debug.javascript.usePreview is no longer known
• js-debug is available via the debug types: node, extensionHost, chrome, msedge and the corresponding pwa- prefixed types.
• installing the deprecated node debug extensions on the Marketplace (node-debug and node-debug2) does not interfere with js-debug: the deprecated debug extensions are only available via the legacy- prefix (this includes legacy-node2). I could still debug node.js programs for node.js versions < 8.0.

[liesauer]

cannot switch back to legacy chrome debugger using legacy-chrome.
it says doesn't support legacy-chrome type.

@connor4312