Docs: Suggestion - remove Bootstrap 4 from footer

[coliff]

Right now at the footer of the site there is a link to Bootstrap's projects on GitHub:

Now that it's been nearly 2 years since Bootstrap v4 went EOL I think it makes sense to remove that link as having it there may indirectly wrongly give the impression that it's supported and/or recommended in some way.

Removing this link may help reduce page rank of Bootstrap v4 pages in search engines and prioritize v5 too :-) (searching for bootstrap carousel in Google for me still shows the v4.0 docs as the top result :-( )

[julien-deramond]

I’m not the only one making the decision, but I agree with removing the Bootstrap 4 reference in the footer. Same thing as for the other issue you created today, feel free to create a PR for it, @coliff, or I can take care of it if you're short on time. Let's see what the rest of the core team thinks once the PR is up.