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?