Rave-python

Changes include
- Update virtual account creation call.
- Code clean-up

Version changes.

- [FIXED] Update "Pay with Bank (NG)" endpoint.
- [ADDED] eNaira payment method.
- [ADDED] Pay with Bank Transfer payment method.
- [ADDED] Tanzania mobile money payment method.
- [ADDED] Support for EUR and GBP on pay with Bank method.

- Add community contribution guidelines.
- Add new content for developer docs.
- Add a new structure for better readability.