Add Timestamped base model (created_at, last_updated_at auto fields).

[arkid15r]

Issue Number

#3019
Introduce Timestamped model base with created_at, last_modified_at auto fields

[davidsmejia]

I'd much prefer we kept created_at and updated_at conventions across models.

[davidsmejia]

Let's update the field name and make a ticket to verify that the new fields don't get auto inserted, I am concerned about there being a timeout, might make sense to add the field and then paginate and insert the values.