Automatically gather metrics about event listener invocations

As of GH-1068, we automatically gather metrics about events published across module boundaries on the publishing side. It would be nice if we could also automatically monitor the state of event listeners handling them. Ideally, we'd calculate a success / error ratio as well.

@marcingrzejszczak — I think this should be pluggable into the standard cross-module invocation instrumentation we already have in ModuleEntryInterceptor, I am just not quite sure about the design of the metric. I'll push a branch with some initial refactoring of the overall infrastructure to a feature branch and craft a draft metric setup that's likely wrong but give a general impression what I want to achieve.

Related tickets

• GH-1068