Added hardcoded auth for testing.

This makes the code work for clusters with auth enabled but the username and password are hardcoded. This is purely testing.

The test username and password:

clone_collection
2dB9K6c5az
Added support for hashed indexes during copy
Added hardcoded auth to compare and copy_stragglers
Added auth for local on compare collections
Added support for background indexes
Reworked to use auth flags and centralize using the utils.mongo_connect
Reworked to use auth flags and centralize using the utils.mongo_connect
Merge remote-tracking branch 'origin/crentralize-auth' into crentralize-auth
Working: allow copying to existing collections
Merge branch 'allow_existing_collections' of https://github.com/mm-/hydra into allow_existing_collections