`get_SDA_interpretation()`: refactor/upgrade ad hoc classification for weighted average method

[brownag]

Use information on specific rule rating class limits and labels rather than limits as shown here

soilDB/R/get_SDA_interpretation.R

Lines 911 to 921 in 7df1979

	"CASE WHEN rating IS NULL THEN 'Not Rated'
	WHEN design = 'suitability' AND ROUND((rating/sum_com),2) <= 0 THEN 'Not suited'
	WHEN design = 'suitability' AND ROUND((rating/sum_com),2) > 0.001 and ROUND((rating/sum_com),2) <=0.333 THEN 'Poorly suited'
	WHEN design = 'suitability' AND ROUND((rating/sum_com),2) > 0.334 and ROUND((rating/sum_com),2) <=0.666 THEN 'Moderately suited'
	WHEN design = 'suitability' AND ROUND((rating/sum_com),2) > 0.667 and ROUND((rating/sum_com),2) <=0.999 THEN 'Moderately well suited'
	WHEN design = 'suitability' AND ROUND((rating/sum_com),2) = 1 THEN 'Well suited'
	WHEN design = 'limitation' AND ROUND((rating/sum_com),2) <= 0 THEN 'Not limited'
	WHEN design = 'limitation' AND ROUND((rating/sum_com),2) > 0.001 and ROUND((rating/sum_com),2) <=0.333 THEN 'Slightly limited'
	WHEN design = 'limitation' AND ROUND((rating/sum_com),2) > 0.334 and ROUND((rating/sum_com),2) <=0.666 THEN 'Somewhat limited'
	WHEN design = 'limitation' AND ROUND((rating/sum_com),2) > 0.667 and ROUND((rating/sum_com),2) <=0.999 THEN 'Moderately limited'
	WHEN design = 'limitation' AND ROUND((rating/sum_com),2) = 1 THEN 'Very limited' END AS [class_%s]"))),

As a benefit we can probably work around the issues with ruledesign in different SSURGO sources RE: #383