Support arbitrarily large EBU R 128 loudness normalization

While i have fixed gstreamer's `volume` in
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5063
i did not see anything that followed after it was merged, namely, in
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6222,
the feature was moved, `"volume"` was reverted to only handle `x10` gain,
and one needs to use `"volume-full-range"` instead to do arbitrary gain.
So let's do that.

This, of course, requires run-time detection of the version
of gstreamer base plugins that we are running with,
specifically, we need version `1.24`.

src/engine/gstenginepipeline.h

@@ -261,6 +261,7 @@ class GstEnginePipeline : public QObject {
 
   // EBU R 128 Loudness Normalization
   bool ebur128_loudness_normalization_;
+  bool gstreamer_supports_volume_full_range_;
 
   // Spotify
 #ifdef HAVE_SPOTIFY