docs: generate sitemaps + change search filters (#8957)

- Generate sitemaps for `book` and `resources` projects (in attempt to resolve some pages not being picked up by the crawler)
- Change the v2 search filters

> Note: will require changes to algolia's crawler + a recrawl once merged

www/apps/book/providers/search.tsx

@@ -74,7 +74,7 @@ const SearchProvider = ({ children }: SearchProviderProps) => {
           },
         },
       ]}
-      initialDefaultFilters={["book"]}
+      initialDefaultFilters={["guides"]}
     >
       {children}
     </UiSearchProvider>