Add feature to drop index with keys json used to create it

[liuchong]

Motivation:

Add ability to drop index with keys json used to create it, no need to get keys from it.

Please check java driver document https://mongodb.github.io/mongo-java-driver/4.10/apidocs/mongodb-driver-reactivestreams/com/mongodb/reactivestreams/client/MongoCollection.html#dropIndex(org.bson.conversions.Bson) and mongodb document https://www.mongodb.com/docs/manual/reference/method/db.collection.dropIndex/

[liuchong]

Please check when you have time @vietj @tsegismont 👀