Type Inference 2: Determine a type for a column

[mathemancer]

Problem

Different types in Mathesar will enable different operations; for example, strings could be aggregated by concatenating, but numeric types could be aggregated by summing or multiplying. So far, while we can reflect different types, we have no way to determine the type most appropriate for a column.

Proposed solution

Using the function implemented for #91 , we should then test the column against types in an algorithmic way to determine the best type prediction we can for the column

[mathemancer]

Marking as blocked until #126 is sorted out.