[Media] Node error reports go nowhere

[waddlesplash]

As far as I can tell, ReportError() may be broadcasted to listeners, but it is not stored anywhere and no applications nor the server listen to those errors.

Additionally, the errors nodes can report are seriously limited. We may need a totally new error reporting mechanism to at least be able to send status_t and a message along with an error instead of a node_error enum value, and said errors probably should be stored in the media_server until a B_OK is sent instead.