Add `Website` Class and View (replaces `ArguSite`)

[joepio]

• [ ] Add a class for Website. This should probably include a list of menuItems which link to Articles
• [ ] Add a view for Website that allows easily creating and editing the sub-articles.
• [ ] Update docs (especially for sveltekit demo)

Thanks @AlexMikhalev

[joepio]

Thoughts @Polleps ?

[Polleps]

I'm not a fan of defining our own opinionated classes for concepts as broad as a website but maybe some kind of preset ontology feature could be nice where you can select a starter ontology that will be created on the users drive and continue from there