LPS-49937 add KBFolder model

KBArticles may now have two types of parents: folder and articles. Add
also a field to KBArticle to indicate the kind of parent pointed to by
`parentResourcePrimKey`:

  - KBArticle: KBArticleConstants.getClassName()
  - KBFolder: KBFolderConstants.getClassName()

The UpgradeProcess will make sure that all existing articles have the
correct parent classNameId:

  - Root articles (parentResourcePrimKey == 0) will have a folder as a
    parent.
  - Non root articles (parentResourcePrimKey <> 0) have an article
    as a parent.
LPS-49937 SF
LPS-49937 SF
LPS-49937 lang keys
LPS-49937 regen
LPS-49937 make portlet aware of parent classNameId

While not all folder logic is in place, make the services and portlets
aware of the classNameId where appropriate. I'll hardcode temporarily
the classNameId so that everything works as before.
LPS-49937 SF
LPS-49937 auto sf
LPS-49937 Autogenerated including service.properties because it wasn't updated with the change of the folders entity in service.xml?
LPS-49937 mvcPath, then tabs, redirect, then other stuff
LPS-49937 only add a break for id, then everything else
LPS-49937 simplify
LPS-49937 SF
LPS-49937 SF
LPS-49937 Don't break up fileName logic
LPS-49937 SF
LPS-49937 SF
LPS-49937 reorganize view JSP

Move things around to make room for an additional search container.
LPS-49937 add stub search container
LPS-49937 Auto SF