Triplanar as a mapping option in the Corona Bitmap

Created based on a forum post, which had ended up with this suggestion:

"simplified triplanar mapping could be implemented straight into Corona bitmap, next to explicit, real world and enviromental mapping modes. So when you don't need advanced parameters of full triplanar node and 95% of the time i don't need them, then you simply could turn on triplanar in CBitmap and be happy."

https://forum.corona-renderer.com/index.php?topic=25750.msg154056#msg154056

and also

https://forum.corona-renderer.com/index.php?topic=25794.0

This already has an entry in our task tracking.