Provide a webhook for Zabbix 6.0

Zabbix 6.0 LTS is out for a few months now.

Zabbix 5.4 gave us a peek of a few changes such as:

• the now preferred YAML format for Zabbix configuration import-export (instead of XML)
• Zabbix JS and internal objects changes: a few methods have had their names changed, so we have to check and update webhook code

Output:

a separate "media type" configuration for the Canopsis webhook, tested against Zabbix 6.0, distributed in YAML format.