Home task for checkout.com

1)Implemented API for proceeding payments + mock implementation of bank service

2)Added authentication using built-in asp.net core Identity system + Jwt-tokens
ways of improvements: sign tokens with certificate instead of secret string

3)Added some example logging using built-in asp.net core logger
ways of improvements: add logging to file using 3rd party logging providers (Serilog etc)

4)Imlemented integration tests

5)Added API client using SwaggerUI

6)Data storage (for saving merchants and payments) - SQL Server Express LocalDB
ways of improvements: switch to another appropriate db

7)Implemented CI using githup actions