[8.x] Added custom methods proxy support for jobs ::dispatch()

[rennokki]

This seems a bit too nested:

dispatch(
    (new SomeJob('value1'))
        ->someMethod(1234)
        ->someOtherMethod('abc')
);

With the current changes, I find the ::dispatch() method a bit more approachable:

SomeJob::dispatch('value1')
    ->someMethod(1234)
    ->someOtherMethod('abc');

Both someMethod and someOtherMethod are custom methods within the job class.