Add organization URLs to link check

[MizukiTemma]

Short description

This PR adds URLs of organizations to our link check/replace feature.

The issue is planned not for Q3 but Q4, but in my opinion it's better to implement this before we start refactoring of link check/replace feature for performance and the centralised link management system.

Proposed changes

• Add the model Organization to the link checker
• Add a new function replace_urls to the model Organization to be compatible with the refactoring from #3003
• Adjust functions for link replacement (because organization objects do not have any translations)

Side effects

• I hope it functions at least. We definately need some refactoring (but suggest to do it in another PR) It's merged now :)

Resolved issues

Fixes: #2369

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