media: Introduce local media playback

Allows local playback of sounds such as "phone-outgoing-calling",
"phone-outgoing-busy".

Helps: https://gitlab.gnome.org/GNOME/calls/-/issues/351

Signed-off-by: Evangelos Ribeiro Tzaras <devrtz@fortysixandtwo.eu>
Part-of: <https://gitlab.gnome.org/GNOME/calls/-/merge_requests/804>

src/meson.build

@@ -34,6 +34,7 @@ calls_deps = [
   dependency('gmobile', version: '>= 0.3.0'),
   dependency('gobject-2.0', version: '>= 2.74'),
   dependency('gom-1.0'),
+  dependency('gsound'),
   dependency('gtk4', version: '>= @0@'.format(gtk_version)),
   dependency('libadwaita-1', version: '>= 1.6'),
   dependency('libcallaudio-0.1'),
@@ -106,6 +107,7 @@ calls_sources = files(
   'calls-log.c',
   'calls-main-window.c',
   'calls-manager.c',
+  'calls-media-playback.c',
   'calls-message-source.c',
   'calls-network-watch.c',
   'calls-new-call-box.c',