daemon: add a mode to execute lua scripts from the command line

This can be useful for quick testing of scripts, or to build small
utilities that do something in pipewire utilizing our lua API

modules/module-lua-scripting/api.c

@@ -101,11 +101,37 @@ core_sync (lua_State *L)
   return 0;
 }
 
+static gboolean
+core_disconnect (WpCore * core)
+{
+  wp_core_disconnect (core);
+  return G_SOURCE_REMOVE;
+}
+
+static int
+core_quit (lua_State *L)
+{
+  WpCore * core = get_wp_core (L);
+  g_autoptr (WpProperties) p = wp_core_get_properties (core);
+  const gchar *interactive = wp_properties_get (p, "wireplumber.interactive");
+  if (!interactive || g_strcmp0 (interactive, "true") != 0) {
+    wp_warning ("script attempted to quit, but wireplumber "
+        "is not running in script interactive mode; ignoring");
+    return 0;
+  }
+
+  /* wp_core_disconnect() will immediately destroy the lua plugin
+     and the lua engine, so we cannot call it directly */
+  wp_core_idle_add (core, NULL, G_SOURCE_FUNC (core_disconnect), core, NULL);
+  return 0;
+}
+
 static const luaL_Reg core_funcs[] = {
   { "get_info", core_get_info },
   { "idle_add", core_idle_add },
   { "timeout_add", core_timeout_add },
   { "sync", core_sync },
+  { "quit", core_quit },
   { NULL, NULL }
 };