Small functionality additions:
- Pandas DataFrame conversion can be done without importing `pandas`, simply use the `to_df()` method, more on README
- Caching on results using `lru_cache`
- Password is an optional argument but will be prompted using `getpass` when not provided, this allows one to conceal their password all the time when using `autokattis`
- Remove nesting on ranklist JSON so the DataFrame version is more usable
**Full Changelog**: https://github.com/RussellDash332/autokattis/compare/v1.4.6...v1.4.7