log: allow dynamic log levels for WpLogTopic
Change design of WpLogTopic so that it allows for changing their log levels at runtime.
Take a simple design where the global list of log level values is never freed. Otherwise, we would need to manage WpLogTopic lifetimes, which makes things more cumbersome.
Add support for pipewire!1811 (closed) pipewire!1824 (merged)
Complements !574 (merged)
This is a bit RFC as there are other designs possible.
Edited by P V