The main change here is that now the official mirrors are the official mirrors managed by cluster adm team.
The other mirrors are now named community mirrors.
-->
Remove all mirrors sections [1] (much outdated information) in favor of a small and unified one [2].
I checked every single mirror (for each protocol) and removed all that is not responding or that has duplicate IPs with another mirror [3].
This was discussed with clusteradm, but the text needs review and possible improvements.
1 - [handbook/mirrors-http](https://docs.freebsd.org/en/books/handbook/mirrors/#mirrors-http), [handbook/mirrors-ftp](https://docs.freebsd.org/en/books/handbook/mirrors/#mirrors-ftp), [handbook/mirrors-rsync](https://docs.freebsd.org/en/books/handbook/mirrors/#mirrors-rsync), [handbook/eresources-web](https://docs.freebsd.org/en/books/handbook/eresources/#eresources-web)
2 - [new section preview](https://dbaio.bs2cloud.com.br/doc/build-2022-02-03-mirrors/en/books/handbook/mirrors/)
3 - [mirrors removed from the list](https://people.freebsd.org/~dbaio/mirrors/mirrors-lists-removed.txt)