masquerade and more async methods

[michaelkryukov]

Changes:

• Added masquerading mock classes as motor's original, so checks like isinstance(collection, AsyncIOMotorCollection) won't fail. It's possible there will still be issues if you expected to use tornado classes instead of asyncio, but I will wait for actual cases to somehow solve this.
• Added some async methods for collection.
• Added test that checks basic compatibility with beanie ODM.

Notes:

• Inspired by Add index_information to mocked methods #1.

[tclasen]

Hey again! Here is my example code base that prompted the previous PR if you want to test against this. If you look at the init_mongo function you can see I'm passing in an arg and a kwarg. If I remove those, your branch les me pass unit tests 100%. Could we also add something to consume excess *args and **kwargs when initializing the client?

https://github.com/tclasen/fastapiplayground

[tclasen]

And also, a HUGE thank you for even making this library. Unit testing async mongo has been such a pain for the longest time. Despite your repo only being a few days old, it is the most complete / working implementation on the market right now.

[michaelkryukov]

Pretty much all the credit goes to mongomock, they did most of the job 😄. Nice to see that I'm not the only one who needed a viable mock for async mongo too. I added *args, **kwargs to AsyncMongoMockClient's __init__. This should fix mocking with AsyncMongoMockClient.

[tclasen]

I just confirmed your newest commit passes all tests in my repo using Beanie.