Run target in debugger

A common workflow for me is to always run binaries (both applications and tests) under a debugger, so that I can immediately investigate what is going on (as a side note, this is very common among Visual Studio users, e.g. in the games industry).

This is very useful to save time and to catch rare bugs, but it empirically only really works if it's convenient enough. Unfortunately, manually typing out `buck-out` paths or hacking around the output of `buck2 build --show-output` is hardly convenient.

Would you be open to adding support for this use-case via a new command/flag (e.g. `buck2 debug` or `buck2 run --debug`)? If so, I'd be happy to discuss the actual design and/or work on the implementation.