Initial Version
**Based on warrant with follow changes:**
- align flow to official java sdk (1)
- Changed 'add_base_attribute' method name into 'set_base_attribute' (2)
- Fix setup install for py37 (3)
- stub units tests (4)
- reset password admin (5)
- changed authflow value in renew_access_tokens (6)
- Fix get_users to return all users
- Migrate to python-jose[cryptography]
- Rebrand pyCognito