Convert to Open-Source repository

[reiche-banane]

I believe this project and its users would greatly benefit from it being open source.

When developing a debug adapter, I encountered some opaque errors, and occasional missing features that could be easily addressed (and contributed back) if the source code was available.

There was some discussion in previous Issues, but this Issue could serve as the place for continued discussion.

[michael-dwan]

This would be a huge benefit to the community. Just wondering if there had been any consideration at Microsoft since this issue was created?