Branding should be configurable

The page titles and headings etc. are currently replete with Pony Mail! references.

It makes sense for the page footer to reference the Pony Mail brand, but it does not really make sense for all the pages to also reference Pony Mail. The site branding should be site-specific.
Likewise the logos.

Start by inventorying the page titles, headings, footer references, and logos that currently use Pony Mail branding. Determine where site-specific branding can be configured and verify that page content uses it while the footer retains the Pony Mail reference. The issue does not name files or tests, so locating those entry points is the first step.

Written by the indexing model from the issue text.