Update model to use consistent Recurrence object

[Samffy]

Add some consistency to Recurrence object.

Before

$recurrence = (new Recurrence())
    ->setFrequency(new Frequency('MONTHLY'))
    ->setPeriodStartAt(new \Datetime('2017-01-01'))
    ->setPeriodEndAt(new \Datetime('2017-12-31'))
    ->setInterval(1);

After

$recurrence = new Recurrence(
    new Frequency(Frequency::FREQUENCY_MONTHLY),
    $interval,
    $periodStartAt,
    $periodEndAt,
    $count,
    $constraints
);