docs: updates to admin customization docs (#7493)

* updated admin docs

* re-add navigation and parameters sections

* update injection zones

* update cli scripts docs

* added list of injection zones

* add details about widget props

* restructure admin injection zones

www/apps/book/sidebar.mjs

@@ -216,18 +216,10 @@ export const sidebar = sidebarAttachHrefCommonOptions(
               path: "/advanced-development/admin/ui-routes",
               title: "Admin UI Routes",
             },
-            {
-              path: "/advanced-development/admin/setting-pages",
-              title: "Admin Setting Pages",
-            },
             {
               path: "/advanced-development/admin/tips",
               title: "Tips",
             },
-            {
-              path: "/advanced-development/admin/onboarding-example",
-              title: "Example: Onboarding Widget",
-            },
           ],
         },
       ],