[5pt] Add "Auto" system to ras_unit_to_s3.py

[RobHanna-NOAA]

ras_unit_to_s3.py, which helps get a ras2fim.py output folder back up to s3, needs an "auto" system. Currently, the script is interactive with the users. It is critical that key folders are in correct locations in s3, so while the script it is running, it stops and asks for user input in various conditions. e.g. move a pre-existing folder to archive, overwrite a folder, etc.

However, this process means it can not run in an pipeline system with automation. What is needed is a new optional "-auto" flag, which if present, the script will automatically make those decisions and not require user interaction.