Select the Epoch type to update code table #31
Description
When user selects the Epoch type from the edit.html dropdown, the codelist_code and code values should be stored in the database code table.
A unique Code_N value is created and stored in the epoch.type column.
The selected epoch value should persist in the UI.
If an epoch value exists, it should be displayed upon rendering the edit.html, epoch-section.
The column codelist_table will appear as NULL.