no way to set current working directory

I'd like the executable under debug to run from a certain directory so that files it creates go there. We don't have an option for that.

Start by tracing how the debug adapter builds the executable's launch configuration and where existing run options are handled. Add a configurable working-directory option, then verify that the debugged executable starts there and creates its files in that directory.

Written by the indexing model from the issue text.