Add options for enable one-time assertExchange calling

[Storm8719]

If no one created exchange before the broker.sendToChannel() was called - we getting AMQP channel error 404 issue. Think it would be useful to add the ability to enable a one-time assertExchange() call before the first publish to a new exchange. So that there is no dependence on third-party services and we know that the exchange will definitely be created

[Storm8719]

Hi @icebob. Thanks for your reply. In the new commit I set a fixed exchangeType and renamed the variables. Regarding the third point: If you mean different exchangeOptions for different calls broker.sendToChannel(channelName, payload, opts) - now we can directly set these values ​​in opts. For example:

this.broker.sendToChannel("some.channel", {
        id: 1234,
    },
    {
        publishAssertExchange: {
            enabled: true,
            exchangeOptions: {
                durable: false
            }
        },
    }
);

Options that are specified directly in broker.sendToChannel will have more priority than ones specified in the general adapter config.

Edits have also been added to the readme with example

[icebob]

Thank you!