Add DAP protocol support

[spdegabrielle]

Making Racket debugging capabilities available to other editors

https://microsoft.github.io/debug-adapter-protocol/

See #145

[ndykman]

Thanks for tracking this. If I have some bandwidth and some guidance as where to start, I might be able to help a bit.

[dannypsnl]

@ndykman You can check the implementation of https://docs.racket-lang.org/drracket/debugger.html