Revise Siren documentation (#6553)

* revise Siren doc

* Fix broken links

* Fix broken links

* broken links

* mdlint

* mdlint

* mdlint again

* Merge branch 'unstable' into book-siren

* test whether I have the required privs :-)

* revise

* some minor siren related changes for the book

* updates re: `--net=host`

* lint

* Minor revision

* Add note

* mdlint

* Merge branch 'unstable' into book-siren

* Merge branch 'unstable' into book-siren

* Merge remote-tracking branch 'origin/unstable' into book-siren

* Fix spellcheck

* Capital letters SSL

book/src/SUMMARY.md

@@ -33,9 +33,8 @@
     * [Signature Header](./api-vc-sig-header.md)
   * [Prometheus Metrics](./advanced_metrics.md)
 * [Lighthouse UI (Siren)](./lighthouse-ui.md)
-  * [Installation](./ui-installation.md)
-  * [Authentication](./ui-authentication.md)
   * [Configuration](./ui-configuration.md)
+  * [Authentication](./ui-authentication.md)
   * [Usage](./ui-usage.md)
   * [FAQs](./ui-faqs.md)
 * [Advanced Usage](./advanced.md)