Record Brand edit history and display dif

[RogerTangos]

AS A person entering brand data
I WANT a brand's edit history to be visible to me via a web interface
SO THAT I can be confident about what changes I or someone else made to a brand.

Dev Details:

• There is at least one django library, django-simple-history that does this in an easy way

Acceptance Criteria:

• A user can click a button from a brand view and see the changes made to a brand and its commentary including either
• changes
  • what fields changed
  • what content inside the fields changed
  • who changed them
• or history
• All of the the brand and commentary's previous fields
• the previous person to change the brand