docs: shift files around to match summary structure

docs/latest/architecture/index.md

@@ -151,7 +151,7 @@ you would need to recreate.
 [viewers-project]: https://github.com/OHIF/Viewers
 [viewer-npm]: https://www.npmjs.com/package/@ohif/viewer
 [pwa]: https://developers.google.com/web/progressive-web-apps/
-[configuration]: ../essentials/configuration.md
+[configuration]: ../configuring/index.md
 [extensions]: ../extensions/index.md
 [core-github]: https://github.com/OHIF/viewers/platform/core
 [ui-github]: https://github.com/OHIF/Viewers/platform/ui