Feature Request: Allow to pass ticket_id to API Feature

[benningm]

Currently it is only possible to pass the ticket_salt to generate the ticket_id.
If you dont have access to the servers ticket_salt it would be good if you can directly
pass the ticket_id to obtain the certificate.

class { '::icinga2::feature::api':
  pki             => 'icinga2',
  ca_host         => 'icinga2-master.example.com',
  ticket_id     => '<insert-id-generated-on-master>',
  # ...
}

Expected Behavior

When a ticket_id is given then it should use the ticket_id instead of generating it
from the ticket_salt and fqdn.

Current Behavior

The ticket_id is generated with an function from the fqdn and the ticket_salt.

In case no ticket_salt has been passed it defaults to the string 'TicketSalt' which
is confusing. It may be better to fail if no TicketSalt is set in this case.

Possible Solution

Add parameter ticket_id to icinga2::feature::api and use it if set.

Context

When the Icinga-Master is not under your control you may only have access to ticket_id
and not to the ticket_salt.

Or in case the module is used in a masterless puppet setup and you dont want store your ticket_salt local.

Your Environment

Applies to any environment.