What:
Add check for container type on queries

Why:
So users of this library get an informative warning when
the first argument of a base-query is not an appropriate container.

How:

1. Created a helper function that does a runtime check on the type of a container.
2. On every queryAllBy* variant called the new helper function with the given container.

Checklist:

• Documentation added to the
  docs site N/A
• I've prepared a PR for types targeting
  DefinitelyTyped N/A
• Tests
• Ready to be merged
  

Some decisions I'd like to point out for review:

• As the base-queries are part of the public API, and to not risk breaking clients, I took a more relaxed approach to type checking containers and only check for the properties querySelector and querySelectorAll, instead of going for something more restrictive like nodeType.
• Although I'm not 100% sure, from the code I read, the types that seem appropriate to be containers are Element, Document, and DocumentFragment. So those were the ones that I referenced in the error message.
• Initially, I added the helper function to the query-helpers.js file as query related functions are the only ones to use it. But then I remembered that query-helpers.js is part of the public API, so I ended up moving the helper function to helpers.js as it seemed like the best place yet.

Please let me know if there's anything that I should change in this PR and I'll get to it :)

Ref: #537