Stop server on SIGTERM by default

[yawaramin]

Fix #174

[Willenbrink]

Looks good!

I was wondering if we should also handle SIGQUIT but that already works. See also this discussion for the common signals to terminate processes. SIGHUP might be interesting at some point.

[aantron]

if we should also handle SIGQUIT but that already works

In what context? I have SIGQUIT working in the shell to terminate Dream servers without this PR.

λ dune exec example/1-hello/hello.exe
03.10.25 07:11:33.858                       Running at http://localhost:8080
03.10.25 07:11:33.858                       Type Ctrl+C to stop
^\fish: Job 1, 'dune exec example/1-hello/hello…' terminated by signal SIGQUIT (Quit request from job control with core dump (^\))

But interestingly SIGTERM also also works:

λ dune exec example/1-hello/hello.exe
03.10.25 07:12:58.001                       Running at http://localhost:8080
03.10.25 07:12:58.001                       Type Ctrl+C to stop
^Zfish: Job 1, 'dune exec example/1-hello/hello…' has stopped

λ bg
Send job 1 'dune exec example/1-hello/hello.exe' to background

λ kill %1
λ fish: Job 1, 'dune exec example/1-hello/hello…' terminated by signal SIGTERM (Polite quit request)

This appears to be an issue inside containers. Is SIGQUIT relevant for Dream servers running inside containers?

[yawaramin]

TODO: reconsider approach for multicore.