[10.x] Accept protocols as argument for URL validation

[MrMicky-FR]

This is a follow-up of #47770 (see last comment, and also #47381), hopefully this is the right one 😃

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This PR makes it possible to specify which protocols are allowed in Str::isUrl and in the url validation rule.

This can be useful in two situations:

• To authorize only some specific protocols (e.g. only https to force secure links)
• To use exotic protocols that are not in the hardcoded protocols list without having to modify the list directly in Laravel

There is no breaking changes, as the default behavior (when no parameters are used) is the same as current: only the protocols in the existing list are allowed.

Example usage:

$v = Validator::make($data, [
    'url' => 'sometimes|url', // current behavior
    'link' => 'sometimes|url:http,https', // only http and https
    'game_url' => 'sometimes|url:minecraft,steam', // also support more protocols such as 'minecraft://'
]);

Also I think that reducing the default list to only http and https (like Symfony, or even just https to force secure links) might be a sensible option, as most of the times a HTTP(S) URL would be expected, but this would be a breaking change for master in a separate PR.