Also rename the intermediate lua api table WpDebug -> WpLog
Keeps things more consistent with the function names (wp_log*),
with the lua api (Log.*) and with pipewire using log.{h,c} as well.
After all, these functions are for logging...
* use the activate/deactivate system from WpObject,
which allows async activation and error reporting
* drop 'module' property, use 'core' from WpObject
After discussing things at the AGL May 2019 F2F meeting
and reflecting on the initial design of WirePlumber,
it became clear that it needed a fresh start.
