[Task] Add librsvg2 to recommended packages

[saitho]

librsvg2 is needed to calculate preview images for SVG files. Therefore it's added to the list of recommended packages, making it visible in the system check module and command.

Changes in this pull request

I had issues with my Pimcore installation not displaying preview images for SVG files in the backend.
After a couple of hours debugging I found out that the package "librsvg2-bin" is needed for it to work.

If I'm not wrong here, I think this should be added to the system requirements check tooling, so other people can get a better idea what may be missing in their setup, when they come across the same issue.

Additional info

My local Pimcore environment runs with DDEV. After I configured the package to be installed, it worked fine.

[github-actions]

Review Checklist

• Target branch (11.3 for bug fixes, others 11.x)
• Tests (if it's testable code, there should be a test for it - get help)
• Docs (every functionality needs to be documented, see here)
• Migration incl. install.sql (e.g. if the database schema changes, ...)
• Upgrade notes (deprecations, important information, migration hints, ...)
• Label
• Milestone

[saitho]

Wrong target :)