Goal: 

• The current mocks for content template details include the last user that created and updated a given template
• The mocks show the first/last name of the user, but that has some flaws (if name changes), so lets show the username instead

Acceptance Criteria:

• Username of the user creating a template is stored on the template as 'created_by'
• Username of the user updating a template is stores on the template  as 'last_updated_by'
• template fetch/list apis should return the username of the creator and the updater