Provide a global settings page for the defaults instead of using unclear "- None -" value

Ok I prepared a first example (untested!) we should extend this to the other settings.

In the next step, we should then also output the selected default value in the form so you know what's the current global default!

Commented some TBD examples, but there are more.

@thomas.frobieter still relevant in https://www.drupal.org/project/drowl_layouts_bs/ → ?

This is already fixed in BS using Layout Options → . Its not on the settings page, it's in the layout options YML file, but that's fine.

Automatically closed - issue fixed for 2 weeks with no activity.