Merge branch '4740-add-mail-alias' into 'develop'

Resolve "add /mail alias"

Closes #4740

See merge request ispconfig/ispconfig3!1291

install/dist/tpl/gentoo/apache_ispconfig.vhost.master

@@ -12,6 +12,8 @@
 <VirtualHost _default_:{vhost_port}>
   ServerAdmin webmaster@localhost
 
+  Alias /mail /var/www/ispconfig/mail
+  
   <IfModule mod_fcgid.c>
     DocumentRoot /var/www/ispconfig/
     SuexecUserGroup ispconfig ispconfig

install/tpl/apache_ispconfig.vhost.master

@@ -9,6 +9,8 @@ NameVirtualHost *:<tmpl_var name="vhost_port">
 <VirtualHost _default_:<tmpl_var name="vhost_port">>
   ServerAdmin webmaster@localhost
 
+  Alias /mail /var/www/ispconfig/mail
+
   <Directory /var/www/ispconfig/>
     <FilesMatch "\.ph(p3?|tml)$">
       SetHandler None