DA: Initial client-server connection

## Summary

Since the DA is a server designed to be launched by and communicate with a client, the first step to building it will be to ensure the launching and stopping processes work properly.

## Completion Criteria
* Can launch the DA from a client
* Support these DAP requests:
* LaunchRequest
* InitializeRequest
* ConfigurationDoneRequest
* Support these DAP events:
* Initialized
* Can close/terminate the DA from a client
* Support these DAP requests:
* DisconnectRequest, TerminateRequest
* Support these DAP events:
* Terminated
* The above actions should work with VSCode a client