Better management of errors in the API

proposal

#1

From @Anthony https://github.com/mesg-foundation/core/issues/292

For now errors can be difficult to catch on the application side, if using Go we can test the error but if using anything else we will just have the message of the error, it could be good to add a “code” error also to make sure that we can catch a specific error


#2

Errors need to implement GRPCStatus() *Status method.
See: