Feature: Track downstream dependencies at the column level

[aleksmirkovic]

Currently, in the lineage view, a table summarizes the number of downstream dependencies. It would be very helpful if this feature was expanded to columns.

The use case is, a schema change upstream adds new columns. Without this feature, the current process is to either manually examine the PR of the change or the downstream tables. With this feature, a dev could identify any columns which are currently not used downstream and decide if they should be added to downstream models.