This is just #62 with rebase done

Close #62

Original description from #62

This library uses console a lot, without ways to opt out from it or let the consumer provides its own logging implementation (eg. using winston or debug).

This PR makes it possible to do so while:

1. not introducing dependencies
2. not changing existing contracts

Example

const client = new AMQPClient('amqp://...');

// opt out
client.logger = null; 

// override
client.logger = {
 debug: (msg, ...params) => { /* custom impl */},
 info: (msg, ...params) => { /* custom impl */},
 warn: (msg, ...params) => { /* custom impl */},
 error: (msg, ...params) => { /* custom impl */},
}