Revert "Handle ctrl+c to gracefully shutdown the server(s)"

[emilk]

Reverts #1613

cargo r -p rerun -- ../nyud.rrd causes this:

[2023-03-21T08:15:56Z INFO  rerun::run] Loading "../nyud.rrd"…

thread 'main' panicked at 'Error setting Ctrl-C handler: MultipleHandlers', re_viewer/src/app.rs:131

   7: core::panicking::panic_fmt
             at core/src/panicking.rs:64:14
   8: core::result::unwrap_failed
             at core/src/result.rs:1791:5
   9: core::result::Result<T,E>::expect
             at core/src/result.rs:1070:23
      re_viewer::app::App::from_receiver
             at re_viewer/src/app.rs:126:13
  10: rerun::run::run_impl::{{closure}}::{{closure}}
             at rerun/src/run.rs:357:27
      core::ops::function::FnOnce::call_once{{vtable.shim}}
             at core/src/ops/function.rs:507:5
  11: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
             at alloc/src/boxed.rs:2000:9

Troubleshooting Rerun: https://www.rerun.io/docs/getting-started/troubleshooting
libc++abi: terminating with uncaught foreign exception


Rerun caught a signal: SIGABRT

Troubleshooting Rerun: https://www.rerun.io/docs/getting-started/troubleshooting

      rerun::crash_handler::install_signal_handler::signal_handler
             at rerun/src/crash_handler.rs:163:25
   3: _OSAtomicTestAndClearBarrier
   4: __pthread_atfork_prepare_handlers
   5: <unknown>
   6: <unknown>
   7: <unknown>
   8: <unknown>
   9: <unknown>
  10: <unknown>
  11: <unknown>
  12: <unknown>
  13: <unknown>

Rerun caught a signal: SIGABRT
Troubleshooting Rerun: https://www.rerun.io/docs/getting-started/troubleshooting

zsh: abort      cargo r -p rerun -- ../nyud.rrd