when relayhost is define in the init.pp, there is nothing call behind it. As it, if you use it like show in the documentation, it don't work.
After reading the code, it look like that the standard usage for relayhost is to use satellite profile that permit to configure postfix to send all email to $relayhost.
There was no intrinsic way to store an encrypted bind password in heira, so added '$postfix::ldapbindpw'.
Converted '$postfix::ldap_options' to be optional or a string or an array of strings.
Modified the ldap-aliases.cf template so that ldap_options can be optional / a string / an array of strings, and then rendered in alphabetical order.
It is less surprising if the puppet module's default configuration matches a standard default postfix configuration.