\brief Remove an object from the database.

The \a object that is to be removed is identified by its object ID and if it is a regular object also \tt objectType.

The JSON that identfies an object looks like this:
\code
{
    "objectType": "objects.images",
    "id": "52b1a94b5a3d8b15b1037ff5"
}
\endcode

The \a operation is the area from which the object gets removed.
It defaults to \l Enginio::ObjectOperation to remove regular objects by default.

\sa EnginioReply, create(), query(), update()
