Allow reinstalling an extension from an extension repository in the extension manager

Thomas Mortagne I tried to give it a go with Claude Code and it generated the following:

• https://github.com/xwiki/xwiki-commons/pull/1703
• https://github.com/xwiki/xwiki-platform/pull/5383

When you have time, could you check it out and verify if it's any good. At least it worked from what I tried, but I don't know 1) if it's the right way to do it and 2) whether this could have broken something else.

It would be great to have that feature which helps a lot when developing extensions (and allows to reinstall extensions in case something is broken).

Thx!