1) Fixed GitHub workflows (revert to not-latest ubuntu, add py 3.10).
2) Reformatted & Cleaned-up README.
3) Updated copyright year.
4) Renamed 'AISHUB_URL' to 'FEED_URL'.
5) Added instructions for updating SHIP & MIB databases.
6) Removed broad function import in module's init.
7) Refactored AIS specific functions into ais_functions.
8) Added tests, tests, tests! Now at almost 100% for functions.