store a list of names into meta[NAME]
currently, meta[NAME] has a single unicode value (the item name).
it could be changed to be a list of unicode item names.
all these names would be valid names for the item, maybe with some preference on the first one (e.g. if we need to display the name).
like for tags, searching for name_exact:foo would automatically search the list for a member "foo".
practically, this would make the following stuff possible: having "alias names" for items make same thing show up at multiple places (like hardlinks in file system) not needing redirect items if you "rename" an item (== add another name to the list) that is linked from other items or from the outside the name list could have zero elements, making the item somehow vanish from the surface (namespace, index) and be "deleted" (but still being there in storage, just not having a name, but still an itemid, revisions, etc.). the name(s) it had before can still be fetched from its parent revision.