settings.as_dict() singleton not reflect the real configuration

[richtja]

Is your feature request related to a problem? Please describe. After a discussion in #5257 we define the following concern: settings.as_dict() singleton gives developers impression that could be called from everywhere. We should call it only as last resource, if the code you are working on it is not receiving the config.

Describe the solution you'd like Try to remove current calls from settings.as_dict() (singleton), but maybe some of those are not possible (to investigate). If all are removed then we could deprecate the singleton (but keep as_dict() for convenience).

Describe alternatives you've considered Better documentation of this.