Implement per client config files

Move the daemon config file loading to a new conf.c file used by
the context to load the configuration. This replaces the module
profiles and some hacks to move properties around.

If there is nothing other specified with $PIPEWIRE_CONFIG_NAME or
a property, the client.conf file is loaded as a fallback.

Update the session manager config file to load the modules via the
config now. Rename the session modules section to another name.

Update pipewire-pulse to also load a specific pulse property file.
This then makes it pssible to assign specific RT priorities for the
pipewire-pulse process.

src/daemon/pipewire-pulse.c

@@ -93,7 +93,7 @@ int main(int argc, char *argv[])
 	}
 
 	properties = pw_properties_new(
-				PW_KEY_CONTEXT_PROFILE_MODULES, "default,rtkit",
+                                PW_KEY_CONFIG_NAME, "pipewire-pulse.conf",
 				NULL);
 
 	loop = pw_main_loop_new(&properties->dict);