PSR-14 Support

[wandersonwhcr]

Griffin has a direct dependency to psr/event-dispatcher.

But we really need it? Can we run Griffin without PSR-14 installs even using Griffin\Event\DispatcherAwareTrait?

How to test it?

If it works, change docs.

Also, suggests PSR-14 via Composer.

[wandersonwhcr]

I think we can't remove PSR-14 requirement because Griffin\Runner\Runner::up and Griffin\Runner\Runner::down methods use Griffin\Runner\Runner::getEventDispatcher internally and it was defined with a typed return.

But we must check it first.