aomenc low resource usage

[Selur]

aoemenc is slow as hell no way around that using other cpu usage values might help a bit, read:
see: https://forum.doom9.org/showthread.php?t=172550

AV1 encoding is still experimental in Hybrid and only available in the latest dev version.

btw. rav1e is a faster av1 encoder which has far fewer options atm.

Cu Selur