Add Buchkontor Teltow and Inmedio Berlin success stories
Ported from https://codereview.tryton.org/421981003/ which was done by @pokoli
Edited by Cédric Krier
This instance will be upgraded to Heptapod 18.0.1 on 2025-07-10 between 14:00 and 15:00 UTC+2
Ported from https://codereview.tryton.org/421981003/ which was done by @pokoli