Add new method code - Enterolert (Idexx) 9230D

[GabrielleParentDoliner]

(2017) IDEXX has Std Method approval for Enterolert and the Std Method code is 9230-D
https://www.standardmethods.org/doi/10.2105/SMWW.2882.197

[MDWQ]

I see labs simply use the method code "Enterolert". IDEXX also lists method code ASTM D6503-19.

[dylanneild]

@BertoRovina an you check with swimmable waters on what the best code to use for this is and incorpriate it into v1.1.