Add Error description json to twilio-java

[DmitryNeverovich]

Do you have any plans to add errorCodes and errorDescription to Twilio java library?

Twilio error codes: https://www.twilio.com/docs/api/errors
Twilio error codes json: https://www.twilio.com/docs/documents/76/twilio-error-codes.json

Reason: some twilio callbacks return only 'errorCode' without any 'error description'. Callbacks do not include 'error description'.
For example: I send twilio sms message, request was failed with error code 21408. Application received error code 21408 from twilio callback url. The callback url call does not includes error description or error message in parameters.
As workaround I requested message by SID, but I see following: "errorCode:21408" and "error_message: null".
I think more reliable to extract error message from twilio json (https://www.twilio.com/docs/documents/76/twilio-error-codes.json) and avoid additional rest call to twilio.

[JenniferMah]

There is currently no plan at this time to add errorCodes and errorDescriptions to the Twilio Java library. I've nothing against it so open to a PR to add support if you see fit.

[manisha1997]

We do not have any plan to add errorCode and errorDescription to Twilio Java Library