[Console] Add SignalMap to map signal value to its name

[lyrixx]

Q	A
Branch?	6.4
Bug fix?	no
New feature?	yes
Deprecations?	no
Tickets
License	MIT
Doc PR

I'm migrating some code to use new SF features, but I have a very little regression.

Before :

    private function setUpSignals(): void
    {
        pcntl_signal(\SIGTERM, function () {
            $this->stop('SIGTERM');
        });
        pcntl_signal(\SIGINT, function () {
            $this->stop('SIGINT');
        });

        pcntl_async_signals(true);
    }

Now:

    public function handleSignal(int $signal): void
    {
        // I need the following line
        $signal = SignalMap::getSignalName($signal);
        $this->stop("Signal {$signal} received.");
    }

As you can see, now in my log I have an int (2, 15), and not anymore SIGTERM, SIGINT.

[fabpot]

Thank you @lyrixx.