core: remove parent_id from the global event

Remove the parent_id from the global event. Remove the parent
and owner from the global object.

Use properties instead to mark parents and owners of objects.

Properties are easier to control for client exported objects and
usually a simple parent/child is not enough. For example, a client
exported node has the client as a parent but also the factory that
created the node.

pipewire-pulseaudio

@@ -1 +1 @@
-Subproject commit f9fce3cb3042486d8015925bf794acd5c4117ba7
+Subproject commit 2308318b39bd769b5059213958193448a4edea27