Detach branding from build process

[SystemsPurge]

A redo of this pull request but much cleaner.
This will clean up the repository and image registry significantly.
Suggestions on how to do this better:

• Make the user provide plain text that is put into predefined html wrapping elements, instead of forcing the user to provide html themselves, this would remove the XHR completely.
• Make the user provide a css directly instead of a json file
• Directory based media discovery instead of providing paths in the json style config.