[Slim4] Add integer formats support to Data Mocker

Created by: ybelenko

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Current progress

Tiny PR to support int32 and int64 integer formats. Now DataMocker generates values in specific ranges for int32 format.

<?php
require __DIR__ . '/vendor/autoload.php';

use OpenAPIServer\Mock\OpenApiDataMocker as Mocker;
$mocker = new Mocker();
$data = $mocker->mockFromSchema([
    'type' => 'object',
    'properties' => [
        'integer_from_1_to_100' => [
            'type' => 'integer',
            'minimum' => 1,
            'maximum' => 100,
        ],
        'float_from_minus3_to_3' => [
            'type' => 'number',
            'minimum' => -3,
            'maximum' => 3,
        ],
        'string_10chars' => [
            'type' => 'string',
            'minLength' => 10,
            'maxLength' => 10,
        ],
        'boolean' => [
            'type' => 'boolean',
        ],
        'array_of_strings' => [
            'type' => 'array',
            'items' => [
                'type' => 'string',
                'maxLength' => 20,
            ],
        ],
        'Object' => [
            'type' => 'object',
            'properties' => [
                'id' => [
                    'type' => 'integer',
                    'minimum' => 1,
                    'maximum' => 10
                ],
                'username' => [
                    'type' => 'string',
                    'maxLength' => 10,
                ],
            ],
        ],
        'Order_referenced_model' => [
            '$ref' => '#/components/schemas/Order',
        ],
    ],
]);

echo json_encode($data, JSON_PRETTY_PRINT);

output:

{
    "integer_from_1_to_100": 45,
    "float_from_minus3_to_3": -1.741,
    "string_10chars": "Lorem ipsu",
    "boolean": false,
    "array_of_strings": [
        "Lore"
    ],
    "Object": {
        "id": 3,
        "username": "L"
    },
    "Order_referenced_model": {
        "id": 1259632416,
        "petId": 350744286,
        "quantity": 331569927,
        "shipDate": "Lorem ipsum dolor sit amet, consectetur adipiscing el",
        "status": "approved",
        "complete": false
    }
}

Related to #3545 (closed)

cc @jebentier, @dkarlovi, @mandrean, @jfastnacht, @ackintosh, @renepardon