Improve information log/response on Exception

There’s been quite some work (https://github.com/lagom/lagom/pull/1262, https://github.com/lagom/lagom/pull/1211 and https://github.com/lagom/lagom/pull/1315) with different approaches to tune what information should be available in case of service responses that are not 2xx values.

In some cases, the same status code is used by different exception (PolicyViolation vs NotFound using 404 and the treatment differs). In other user requests, the fact that data is withheld in Mode.Prod is counterproductive since staging environments run Lagom in Mode.Prod but are safe (and expected) to report details in case of failure.

These use cases should be considered in an exception handling overhaul.

/cc @guizmaii @smagidson @zmarois

[stijndehaes]

Maybe we can make it configurable through config like this(naming still needs to change):

lagom.logging {

	default = "WARN"
	
	exception.logging.level = {
	  "com.lightbend.lagom.javadsl.api.transport.BadRequest" = "WARN"
	  "com.lightbend.lagom.javadsl.api.transport.Forbidden" = "ERROR"
	}
}

This way people can add their own exceptions to the list

[zmarois]

That’s fine @stijndehaes. Your PR lays our a good start I could tack on status-code-based configuration to, although I’m a little concerned that the status-code-based configuration provides a super-set of the case specific classes, making the mechanism to configure it more-complicated than need be if both exist.