Add parallelism Tiles to encoder

Hi, in vvenc cl application u can add --Tiles 2x2 maximum 5x5 for 1080 and 3x3 1280x720 it will increase encoding parallelism, i currently use a cpu with 36 cores and the your application uses only 12% and peek to maximum 40% of my cpu, so adding tile will increase encoding speed.
Also for high presets above medium u can add --CTUSize 64 also increase encoding speed

Regards

