Remove aliases for NASIS columns, replace with physical column name

[brownag]

Will close #242. Nearly time to rip off the band-aid. For now just a draft PR to facilitate testing.

This is a breaking change for many things that rely on soilDB to query NASIS. It can be difficult to explain to new soilDB users why some columns are aliased and others follow the data model. It will be good to rely on the defined physical column names and standard associated metadata for better parity with internal NASIS queries, web reports, and the official data model in general.

Removes the following aliases in use in fetchNASIS()- and fetchVegdata()-related functions.

Replacing with NASIS physical column name as follows:

• site_id => usiteid
• pedon_id => upedonid or assocuserpedonid (as needed)
• describer => descname
• vegplot_id => vegplotid
• vegtransect_id => vegtransectid or vegtransectiid (as needed)
• x_std => longstddecimaldegrees
• y_std => latstddecimaldegrees
• elev_field => elev
• slope_field => slope
• aspect_field => aspect
• es_classifier => siteecositehistory.classifier (distinguished from classifier which is petaxhistory.classifier)
• sand => sandtotest
• silt => silttotest
• clay => claytotest
• genhz => dspcomplayerid

Aliases are still used for the foreign key columns that end in "ref" as many soilDB queries target multiple related tables, so it doesn't always make sense to include "ref" and users benefit from the shorter name e.g. peiid rather than peiidref

[dylanbeaudette]

It is probably time. We should make sure that as many people as possible know about this as it is going to break a lot of code.

What is assocuserpedonid ?

[brownag]

What is assocuserpedonid ?

This is the "Associated User Pedon ID" in the Vegetation Plot table.