There are currently 1,000+ lines of code in the x/mongo/driver/operation package that are mostly for setting fields on operation structs and passing through fields to the driver.Operation struct. That code provides no increase in usability but is a maintenance burden whenever we need to update operations. We should remove the x/mongo/driver/operation package and move the command document creation and result document decode logic into the mongo package instead.

Definition of done:

• Removing the x/mongo/driver/operation package. Move the command document creation and result document decode logic to the mongo package.
• (Optional) Consider marking all field setters as deprecated in the v1 branch.