[horde] horde6 + nginx + docker

[A. Schulze]

Hello,

Running horde5 + nginx as Dockercontainers for a decade or so, I  
thought it would be time to support horde6 development. Updateing my  
current, private horde5 setup to horde6 doesn't work because I not  
familiar with the new composer setup path and the new filesystem layout.

I'll build my containerimages myself and like to start from scratch with
- debian:triexie-slim
- nginx:trixie

Anybody did similiar things before and can me point to Dockerfiles to  
get some inspiration?

Andreas