Add methods to route all ES commands to bulk

[AnatolyRugalev]

Just look at this code:

$models = EsPost::find()->andWhere(['author' => $id])->all();
foreach($models as $model) {
    $model->doSomething();
    $model->save();
}

This produces multiple ES requests, but it is really possible to make a bulk of them:

$models = EsPost::find()->andWhere(['author' => $id])->all();
EsPost::getDb()->beginBulk();
foreach($models as $model) {
    $model->doSomething();
    $model->save();
}
EsPost::getDb()->executeBulk();

What do you think?

I already implemented this feature and can make a PR if you are interested

[beowulfenator]

That's a great idea. So a connection goes into "bulk mode", operations get accumulated internally, and then executed in one fell swoop with executeBulk?

Go ahead and submit your PR!