libVLC logging API fixes

As reported during our VLC meeting at FOSDEM

added Component::Core Severity::normal Type::bug Version::master git + 1 deleted label

changed milestone to %2.1 features

added Status::fixed label

closed

commit ae3b867b Author: Rémi Denis-Courmont remi@remlab.net Date: Mon Mar 18 23:07:53 2013 +0200

libvlc: simplify and clean up external logging API (fixes [#8129](https://code.videolan.org/videolan/vlc/-/issues/8129))

 - Scope the callback to its instance.
 - Avoid leaking the layout of an internal data structure.
 - Future-proof passing of extra informations through an opaque pointer.

Original author: remi@remlab.net