Feature: Replace links

### Feature description

Remove outdated **Codeberg** link (6 months behind main) in the footer on all pages.
Remove **Codeberg** and **Gitlab** link on the download pages (also not up to date).

### Feature implementation

For the footer the Codeberg link could be replaced with the Bluesky link:
https://bsky.app/profile/freecad.org

Locate the shared footer and the templates or content used by the download pages. Remove the outdated Codeberg link from the footer, replace it with the provided Bluesky link, and remove the Codeberg and GitLab links from download pages. Verify that the links are absent or updated across the affected pages.

Written by the indexing model from the issue text.