Description
We should support Semaphore Locks with a MongoDB back end to allow those that already use MongoDB as a distributed storage engine.

Symfony already partially supports MongoDB for session storage: Symfony\Component\HttpFoundation\Session\Storage\Handler\MongoDbSessionHandler

Example

$client = new MongoDb\Client();

$store = new Symfony\Component\Lock\Store\MongoDbStore(
    $client
    array(
        database: '%mongo_database%'
        collection: lock
    )
);
$lockFactory = new Symfony\Component\Lock\Factory($store);
$lock = $lockFactory->createLock('my-resource');