Add new Fediverse page

[Ainali]

Description

Add a dedicated page for all Fediverse accounts. That makes it possible to download all Fediverse accounts in one TSV file.

This PR moves the explainer text about the Fediverse from the Fediverse statistics page to this one and adds a link here from the footer.

Creating this PR even if we are moving to more use of faceted views in the future, as it seems like it could be useful to people until we get to refactor for that change.

Issue Reference

Fixes #620

Checklist

Please ensure the following before submitting the PR:

• I have tested the changes locally, and they work as expected. (When testing locally, it can be easier to get through a full build by changing views.yaml and countries.rq to only include a few countries with Fediverse accounts and some without, for example, Singapore, Latvia and Greenland).
• The code follows the project's coding standards and conventions.

Screenshot

With limited set of countries as explained in the test above.