i can’t answer this question for you for a backend module, but maybe @bwaidelich can help you.
If you want to use the settings in a Neos-Site though, i would suggest you to create a NodeType that inherits from Document that you only use as your Entry page (Home). There you can add all the required settings you need only once / globally on your site. And it’s also much easier to access those settings in the fusion prototypes as you can simply write sth like this:
Ah, sorry, I completely misinterpreted your question. So you just want to use the Neos Editors (in this case the AssetEditor) wihtin a custom backend module!?
Still, the new media-ui repository might be a good source of inspiration since that uses editors in a new backend module as well.
Okay, it’s a good idea to use the HomePage-document-nodetype to put these global (design)settings like “logo, favicon, fontcolor & fontfamily” into a new tab (to be able to use the Neos Editors)!
Thanks and I will have a look into “flowpack/media-ui”, especially to GraphQL for querying assets, because I think I have to implement it by my own, what I want to achive
For site settings a dedicated tab on the HomePage node is by far the best and easiest way. I did not get what you were up to from your original question.