Add static method to create OR criterion.

Currently the only way to create an $or only query is counter intuitive and leads people to creating $and combined criterions to a single element $or as outlined below.

query(where("title").is(...).orOperator(where("content").is(...))

{
  "title": ...,
  "$or": [
    {
      "content": ...
    }
  ]
}

The correct, rather cumbersome usage would be as follows:

query(new Criteria().orOperator(where("title").is(...), where("content").is(...)))

Introducing a static or(Critieria... criterions) method would allow for simpler usage

query(or(where("title").is(...), where("content").is(...)))

Start by locating the Criteria class and its existing orOperator API, then review nearby tests for criteria construction. Done means the requested static or(Criteria... criterions) entry point supports the simpler query form shown in the issue and is covered by appropriate tests.