Add `payment-logging` service for tracking auto payments

[kvagajack]

This service will be used to log all automatic payments that are done.

Service name: payment-logging. Fields:

• amount;
• address (of a receiver);
• transactionId (id of the Blockchain transaction);
• purpose (e.g. "twitter reward" / "ico payment" / "questionnaire payment");
• status (0 is OK, 1 is ERROR);
• message (e.g. error message);
• dates.

[elliot-tio]

Unable to test directly on QA - not in use yet.