added branding option via '@ <logo>' or '@ <name>' after the CodiMD logo and text.
This was a user can personalize their CodiMD instance
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Co-authored-by: Erik Michelson <github@erik.michelson.eu>
Co-authored-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
