Peerberrypy

- Fix get_loans_page() method functools bug (Credit to rafalkrupinski).

- Change return types to include more data for specific endpoints.
- Type hint fixes and backward compatibility for Python 3.8 and earlier.
- Change numeric datatypes to use decimal.Decimal for improved accuracy and precision.
- CI/CD matrixes and testing changes.

All credit goes to rafalkrupinski for these contributions.

- Bypass CloudFlare protections for Peerberry API.
- Allow supplying access token to boot up session immediately without needing to login.
- Fixed and reworked loan and investment filters.
- More validations and more explicit function arguments.