Horizon ID harmonization in fetch functions

[brownag]

When a data source already has a logical unique horizon identifier, the fetchX() functions should use it instead of the default of calculating one with 1:nrow(spc@horizons)

fetchNASIS_pedons(): hzidname(spc) <- 'phiid'
fetchNASISLabData(): hzidname(spc) <- 'phiid'
fetchPedonPC(): hzidname(spc) <- 'phiid'
fetchRaCA()$pedons: hzidname(spc) <- 'phiid'

fetchNASIS_components(): hzidname(spc) <- 'chiid'

fetchKSSL(): hzidname(spc) <- "labsampnum"

fetchRaCA()$samples: hzidname(spc) <- 'sample_id'

fetchNASISWebReport: hzidname(spc) <- 'chkey'
fetchSDA_component: hzidname(spc) <- 'chkey'

Any objections? Any ones I missed? I am thinking this standard will be handy with implementation of horizon setter changes in aqp