This is intended to allow override of look/feel without overriding the
logic/structure of templates. In practice the main goal internally is
to allow testing of Vue 3 + Oruga, to eventually replace Vue 2 + Buefy
as the default theme.
this definitely needs some more work. using pyramid_mailer for
testing although not ready to declare that dependency. for now this
is "broken" without it being installed.
