Signal handling

[kim]

Since #2011 , it is no longer possible to stop spacetimedb start by ^C. Killing the parent (spacetimedb-cli) will leave the child (spacetimedb-standalone) running.

OS: Linux

[kim]

Of course, sometimes it does work.
I wonder if it may have to do with using the blocking process::Command inside an async function. Afaik, tokio‘s process::Command has extra machinery for signal handling.

[coolreader18]

Going back to using exec() should fix this on unix; I might look into whether this might also happen on windows.

[bfops]

(We definitely need to determine whether this happens on Windows before considering this done)

[bfops]

We should look for a library that abstracts over these platform-specific differences for process management.

If none exists, we'd like to copy the rustup code that solves a similar problem (and include comments that say "we copied this from rustup, pls no change")