Introduce for richtext editors the concept of "preset"
A preset is an abstract set configurations designed to address a specific use case. An example could be a preset for a "minimal" richtext editor, used in those forms where we want to limit the features a user should have access to. Other presets could address specific usages or applications.
Downstream developers can provide a set of ::richtext::$editor::preset::$preset procs, returning an options dict. This set of options will be merged other local configurations. The same approach works in ad_forms and xowiki forms.
This also enables the use-case of switching to a different editor maintaining the existing application-specific configurations consistent.