arcticdatautils function pid_to_eml_physical only works for ADC

[dmullen17]

arcticdatautils::pid_to_eml_physical is one of most useful functions but specific fields only work for uploads to the Arctic Data Center.
For instance the following creates the online distribution info link:

phys@distribution[[1]]@online@url <- new("url", paste0("https://cn.dataone.org/cn/v2/resolve/", 
            x@identifier))

We should generalize this function to work across all (or alot) of the dataOne member nodes - definitely test ADC to start.

[amoeba]

Hey @dmullen17, what's arcticdatacenter specific about that line of code? That would be correct for all nodes in the production environment. One bug I see is that it doesn't work for non-production nodes which would be a nice improvement.

[dmullen17]

@amoeba Yea I specifically had test in mind when i wrote that.