Track changes for tables?

Tracking changes to tables came up in this week's discussion with @bharathydasan and @wendell. There may not ultimately be a need for this, but if there is, it can come after the initial TC implementation.

This could also be potentially very complex. @wendell suggested that as a way to limit the scope/complexity of a solution, a simple whole-table before/after comparison could be surfaced, rather than a granular representation of the specific changes.