withDefaultConfig does not work properly with url connection strings about rascal

[cressie176]

Thanks @matt1097, I'll take a look

[cressie176]

It's a very long time since I wrote this part of Rascal (8 years), however this was intended behaviour, and there's a test to assert it.

I think my reasoning was that if you specify a URL, then it overrides any explicitly specified individual connection attributes. The presence or absence of options in the url is taken as what was intended. I can see how it is counter intuitive though.

I will give some thought as to whether it might be better to merge the specified connection options with any query parameters specified in the url.

[cressie176]

I've updated Rascal's configuration to merge values source from a connection url with those provided as individual attributes, favouring the connection url if both are present.

At the same time I've made a few other hygiene changes, such as removing attributes from the connection properties that aren't directly related to amqp connections (e.g. auth, query, pathname), and regenerating the URL from the derived properties so that the url is consistence once all the defaults have been applied.

I'll release as v17 shortly.