Restore JSON Export option

Summary

At the AWS structure, the JSON Export option is not available. It was possible to enable this at the bundled Add-ons, but after our infrastructure changes, the option to enable the add-on is unavailable as we can see on the following screenshots:

Steps to reproduce

1. List Any JQL
2. Try to export to JSON - Not available.

Expected Result

• The possibility to export to JSON

Actual Result

jira-importers-plugin also called jim-plugin is a bundled system add-on that has some modules disabled by default. It was possible to enable them in the past, providing the ability to export and import issues using JSON.