[Java] Replace AMQConstant class with constant integer error codes

The AMQConstant class is weird and permeates through the equally weird AMQException hierarchy. Essentially the class in 95% about defining the common error codes (404 means Not Found, etc). The AMQConstant class is used broker wide, but does not actually fit to the AMQP 0-10 or 1.0 models.

In AMQP 0-8 we should use the integer error codes, in common code we should use protocol independent enumerations to define possible error conditions