Remove Saber (vercel#1052)

A new Saber stable release last occurred on
[2020-05-19](https://www.npmjs.com/package/saber?activeTab=versions) and
a new alpha release on
[2022-02-15](https://www.npmjs.com/package/saber/v/0.12.0-alpha.20). It
did not reach 1.0 and appears to require Node 16, which is being
discontinued 2025-01-31.

It not referenced in contentful currently.

Author: trek