Allow for multi-value SAINT imports

[#1]

I would like to upload multiple values in a single classifcation for example if I configure a company classification I would like to load 3 different companies into that classification per key. This would have the same effect as if I had populated a list var or list prop using on page tracking only this works via the SAINT import. 

I have many use cases where our preference is to import this data via SAINT but we can't due to it's inability to deal elegantly with single classificaitons that have multiple values per unique key.