Add Service Tagging Capability

[XedinUnknown]

Now you can tag your services, like so:

[
    'serviceA' =>
        /** @tag letters */
        fn (): string => 'A',
    'serviceB' =>
        /**
         * @tag letters
         */
        function (): string {
            return 'B';
        },
    'serviceC' => function (ContainerInterface $c): string {
        var_dump($c->get('letters'));
    },
];

For every unique tag, an extension is added that resolves tagged services and adds them to the list. The list is ensured by also creating an empty list factory with the same name.

[XedinUnknown]

Looking good!

@Biont has also had a look at this, and I have received positive feedback.

Thanks, all!