VAAPI: Change some loglevels - we are spamming too much

By default we log a whole lot of things on NOTICE level, but whenever a problem arrises we ask the user for a debuglog anyways. So this PR moves debug information (e.g. starting of threads and so on) to LOGDEBUG.

Perhaps we should also adapt to the component logging - to not spam other devs when they debug something non VAAPI related.
IMO thread creation is something very basic and we log this in other components as notice too. with this enabled we can at least vaguely spot a dead lock even if debug logging is not enabled.

If you put this into question we can drop LOGNOTICE completely?