Add backend service configuration guide trusted proxies and fix images (#639)

* Add backend service configuration guide for reverse proxy trusted proxies

Many self-hosted services (Jellyfin, Home Assistant, Nextcloud, Plex)
require a "trusted proxies" or "known hosts" setting when behind a
reverse proxy. With NetBird, the proxy's IP is a dynamic NetBird IP
from 100.64.0.0/10 that can change on restart, so hardcoding it breaks.

This adds a new doc page with the recommended solution (trust the full
CGNAT range), per-service config examples, Docker bridge network
guidance, and a warning on the reverse proxy overview page.

* Update service-configuration.mdx and move/add images

* Fixing typos

---------

Co-authored-by: Brandon Hopkins <brandon@techhut.tv>

src/components/NavigationDocs.jsx

@@ -287,6 +287,10 @@ export const docsNavigation = [
             href: '/manage/reverse-proxy/authentication',
           },
           { title: 'Access Logs', href: '/manage/reverse-proxy/access-logs' },
+          {
+            title: 'Service Configuration',
+            href: '/manage/reverse-proxy/service-configuration',
+          },
           {
             title: 'Expose from CLI',
             href: '/manage/reverse-proxy/expose-from-cli',