Add support for turning off signal handler that prints backtrace

[VictorYing]

Enable modelers to disable Sparta's signal handlers, since it conflicts with other framework like SST. No change to default behavior.

[klingaard]

Hi Victor, thank you for the submission!

Instead of adding a new construction parameter to the Simulation class, add this behavior to SimulationConfiguration.

Then, move the backtrace_ set handler calls to this function of Simulation:

if(sim_config_->install_signals_handlers) {
   ...
}

Much appreciated!

[VictorYing]

Thanks for the feedback. It led us to find an existing variable SimulatorConfiguration::signal_mode that seemed to exist for this purpose but have no effect previously, so we simply hooked it up in Simulation::configure() as you suggested.

[klingaard]

Looks good. Thanks for the update. I've asked Tim in the other PR to update MacOS CI.

[klingaard]

Hey @VictorYing, can you pull from the latest master of sparta into your fork? The CI issue has been resolved.