Custom RGB from band formulas

Arithmetic (+ - * / ( )) on bands B02 B03 B04 B05 B06 B07 B08 B8A B11 B12 (aliases RED GREEN BLUE NIR SWIR1 SWIR2 REDEDGE1). One NDVI-like formula per channel, each auto-stretched. e.g. (B08-B04)/(B08+B04)