nextcloud: Redirect to URL nextcloud/ if ending slash is not given

Tests:

- Without the changes, typing https://<domain>/nextcloud does not work. With the
changes it redirects to https://<domain>/nextcloud/.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/nextcloud/data/usr/share/freedombox/etc/apache2/conf-available/nextcloud-freedombox.conf

@@ -18,6 +18,15 @@ Redirect 301 /.well-known/nodeinfo /nextcloud/index.php/.well-known/nodeinfo
 
 Alias /nextcloud/ /var/lib/nextcloud/
 
+# Redirect /nextcloud to /nextcloud/.
+<Location ~ ^/nextcloud$>
+    <IfModule mod_rewrite.c>
+        RewriteEngine On
+        RewriteCond %{REQUEST_URI} ^/nextcloud$
+        RewriteRule .* /nextcloud/ [R=301,L]
+    </IfModule>
+</Location>
+
 <IfModule proxy_fcgi_module>
     ProxyPassMatch "^/nextcloud/(.*\.php(/.*)?)$" "fcgi://localhost:9000/var/www/html/$1"
 </IfModule>