Add B1 Systems to commercial support page (#252)

Signed-off-by: Tilman Lüttje <luettje@b1-systems.de>
Signed-off-by: Bernd Ritter <ritter@b1-systems.de>
Co-authored-by: Bernd Ritter <comrad@posteo.de>
Co-authored-by: Bernd Ritter <ritter@b1-systems.de>

Author: b1-luettje