Constrain `samp_pooling` term [MIXS:0001153]

[sujaypatil96]

Attached is a report from @turbomam on the usage of the samp_pooling term across samples in NCBI BioSample: ncbi_metadata.biosample_attributes.samp_pooling.csv

We see values with a lot of free text that don't add too much value to a software program/system because it's not structured/parseable. This issue/discussion is a request to constrain the semantics of the term in such a way that it's more structured/parseable.

[turbomam]

That's a partial result that @sujaypatil96 and I were reviewing while I was refreshing the database. Here's all values used in that field for the whole NCBI Biosamples Database as of last week.

@sujaypatil96 's point still holds

ncbi_metadata.biosample_attributes.samp_pooling.csv

[mslarae13]

@sujaypatil96 @turbomam is there a proposal for what this constraint should be? Or do we need CIG input?