[CLI] [UX] cbtransfer should fetch the KV error map and translate known errors

What's the issue?
'cbtransfer' and all the tools built upon it, doesn't translate errors returned by 'memcached'. This results in cryptic error messages which (without prior knowledge) are hard to understand/take action on.

What's the fix?
From what I recall, the SDKs fetch the error map (translation table) from 'memcached' on bootstrap (or sometime soon after). This is then used to translate errors into something more user friendly. 'cbtransfer' should do the same.

Is there a workaround?
Yes; the error message contains the error code as an integer, this can then be converted into hex, and once again translated using the documentation.