On saving of Pod with multiple fields, use dbDelta

[sc0ttkclark]

Issue Overview

When saving a pod with multiple fields, each field gets added individually. That's OK but they get added to the DB before all fields are properly validated. What we should do is save the fields to the config and then do the dbDelta() at the end of that saving routine so we catch any problems per field that would send back an error.

This prevents cases where you add 2+ fields, save the pod, one of the later fields has an error, and then when you fix that error and save again there's an SQL error that the DB column already exists.

[sc0ttkclark]

dbDelta makes a lot of sense here to reduce overall logic