GitLab

* Schleuder: port invocation syntax to Schleuder 3.

Schleuder 2.x has been deprecated for a while. It's not maintained
anymore, has obsolete dependencies, and has been superseded by
Schleuder 3.

The new syntax is documented on
https://schleuder.org/schleuder/docs/server-admins.html#postfix

* compatibility with Schleuder 2 can be used this way:

  use_schleuder => 2

* support explicitly setting use_schleuder to 3.

A Boolean "true" value will thus mean "assume the latest upstream Schleuder
release". For now, that's 3.x so setting this parameter to 3 is equivalent
to setting it to true. But once Schleuder 4 is out, this may change,
so better provide users a way to hard-code the fact they have Schleuder 3.

It is an optional array of strings containing addtional entries for the
master.cf file

To be able to configure master.cf with chroot

  Remove has_variable? and scope.lookupvar from templates
  Add parameters to postfix::files
  Pass parameters from postfix to postfix::files