[11.x] Fluent numeric validation

[xoesae]

Description

This pull request introduces a new fluent numeric validation class, offering a more elegant and expressive way to define numeric validation rules.

Before this PR, numeric validation required string-based rules:

$rules = [
    'score' => 'numeric|integer|multiple_of:10|lte:some_field|max:100',
];

$validator = Validator::make($data, $rules);

if ($validator->fails()) {
    return $validator->errors();
}

To use the fluent numeric validation:

use Illuminate\Validation\Rule;

$rules = [
    'score' => [
        Rule::numeric()
            ->integer()
            ->multipleOf(10)
            ->lessThanOrEqual('some_field')
            ->max(100);
    ],
];

$validator = Validator::make($data, $rules);

if ($validator->fails()) {
    return $validator->errors();
}