Add codec_options to ClientEncryption class

The ClientEncryption class has two methods which require a user configurable CodecOptions:

1. ClientEncryption.encrypt which accepts a BSON encodable value.
2. ClientEncryption.decrypt which decodes the decrypted BSON value.

We can either:

• add a codec_options argument to each method
• add a codec_options argument to the ClientEncryption class

I propose we add codec_options to the class to be more consistent with MongoClient/Database/Collection class.