Provide Jira integration for our Alerting system

# Description

Provide a way to integrate Jira with Graylog Alerts. Having our own Jira Notification would make it easier for users to create a Jira ticket when an Alert is raised in Graylog, which they could then manage as they do with other Jira tickets in their organization.

As far as I could see, integrating Graylog Alerts with Jira at this point of time requires to use a Script Notification, which is available as part of Graylog Enterprise, and would still require the customer to write their own script using the [Jira API](https://developer.atlassian.com/server/jira/platform/rest-apis/).

Before we redesigned our alerting system in 3.1, it was also possible to use the [graylog-jira-alarmcallback plugin](https://github.com/magicdude4eva/graylog-jira-alarmcallback). The plugin might still work using the legacy compatibility layer we still provide (although I could not test it with a real Jira instance), although that is marked as deprecated and will be removed at some point in the future.

## What

Make it possible to create Jira tickets when an Event occurs, and include parts of that Event in the Jira ticket.

## Why

Jira is a tool with many users out there, and I think it would be worth it for us to provide an easy to use integration to it.

See HS-595631918 for additional context.