Add a way to break the debugger when it runs

[rjmholt]

The ISE has Ctrl+B to interrupt the pipeline, and the ConsoleHost uses Ctrl+Break.

We should support something similar to

1. Hook into the pipeline to break it while it's running
2. Allow implicit breaks for things like setting breakpoints (like in Debug Session not respecting Added or removed Breakpoints & Integrated Shell Crash #1494)
3. And allow a VSCode hotkey configuration for breaking the pipeline as well.

[rjmholt]

This works currently with F6.