Add debug namespace VSCode API

[lucas-koehler]

Feature Description:

Provide all methods of the VSCode API's debug namespace.

• addBreakpoints
• asDebugSourceUri
• removeBreakpoints
• startDebugging (plugin: align startDebugging api #10656)
• stopDebugging (debug: add support for stopDebugging api #10638)

[lucas-koehler]

@vince-fugnitto Do you currently work on or plan to work on the other methods or are they open to do?

[msujew]

@lucas-koehler There is currently a PR to align the startDebugging API parameters, although it has been in place for quite a while. #10656

[vince-fugnitto]

@vince-fugnitto Do you currently work on or plan to work on the other methods or are they open to do?

@lucas-koehler you can work on them if you'd like, two of them should be quite simple (minor method signature alignment).
I noticed however that there is quite a lot of bugs from the debug namespace, I've opened issues of what I found. Note that the report to show that APIs are completed is not entirely truthful, the methods can be stubbed and/or can be completely non-functional.

[lucas-koehler]

@vince-fugnitto For now, I am not working on them. I decided to go with #9992 instead. But I'll keep it in mind, thanks :)