Sapimclient

Fix export Payments

Removed `to_csv` line intended for testing.

fix missing option --period in cli export command

Fix envvars on CLI commands

Export Credits, Measurements, Incentives, Commissions, Deposits and Payments to TXT with CLI commands.

Automatically expand fields on resources.
Add Reference to other resources.

What's Changed
* V2 by niro1987 in https://github.com/niro1987/python-sapcommissions/pull/20


**Full Changelog**: https://github.com/niro1987/python-sapcommissions/compare/1.2.1...2.0.0