add quota-plugin parameters to dovecot-config-templates; update standardcustomer index.html; set nameserver disabled by default

Signed-off-by: Michael Kaufmann <d00p@froxlor.org>

lib/configfiles/buster.xml

@@ -4079,6 +4079,15 @@ plugin {
   # the source line numbers.
   #sieve_trace_addresses = no 
 }
+]]>
+							</content>
+						</file>
+						<file name="/etc/dovecot/conf.d/90-quota.conf" chown="root:0"
+							chmod="0644" backup="true">
+							<content><![CDATA[
+plugin {
+  quota = maildir:User quota
+}
 ]]>
 							</content>
 						</file>