Add error code and handlers

[sigrlami]

Monobank Api doesn't contain proper description for API error codes. We need to do deeper investigation and integrate them for better user experience. I found so far:

• Invalid Account
• Uknown Token
• Too Many Requests
• Internal Error
• Missing Required Field
• Period Must be no more than 31 days
• Value to must be greater than from

Some of them can be encoded as client interface before actually calling the API. Like, check for 31 days period.