Add more endpoints to Angaza connector

There might be possible relevant data in more endpoints from Angaza. We are currently only reading /payments /clients and /accounts.

TODO: add endpoint "replacements" and endpoints for the following:

• https://payg.angazadesign.com/data/user_credit_adjustments/{identifier}
• https://payg.angazadesign.com/data/remittances/{identifier}
• https://payg.angazadesign.com/data/bonuses/{identifier}
• pricing groups (#997 (closed))
• compare difference between payments and user transactions