Added rewrite rule for apple autoconfiguration url

Rewrite rules are no inherited by virtualhosts when they are declared in conf.d
This means that you'll have to explicitly include SOGo.conf from 000-default
on debian/ubuntu for this redirection to work properly.

Apache/SOGo.conf

@@ -66,3 +66,9 @@ ProxyPass /SOGo http://127.0.0.1:20000/SOGo retry=0
   Allow from all
 </Proxy>
 
+# For apple autoconfiguration
+<IfModule rewrite_module>
+  RewriteEngine On
+  RewriteRule ^/.well-known/caldav/?$ /SOGo/dav [R=301]
+</IfModule>
+