* fix eni lookup logic to update them only when univocally specified (Fixes#19972)
remove redundant eni lookup
* Rename the univocally_find_eni method to uniquely_find_eni
* Idempotency logic minor fixes
* Fixing pep8 reported issues
* Adding a required_together constraint for instance_id and device_index
* Fix ec2_eni private_ip_address matching
* Adding an example of matching via subnet_id and private_ip_address
* Removing the required_together and subnet_id constraints
* Addding some notes to explain the module assumptions
* Implementing Ryan's wording proposal