feat: allow repl pause on exception state to be set from env

Right now, it's not possible to configure the debugger to pause on uncaught exceptions without manually configuring the pause state on each run. This change would allow the pause state to be configured via a shell env variable to allow for faster CLI-based node debugging.

I'm not sure if there's a reason there aren't more configuration options for node inspect, so I wanted to submit this PR for discussion before writing tests and updating documentation.