Torizon: Update Torizon base images to version 4

Replace deprecated debian-cross-toolchain with cross-toolchain
and update base image version from 3 to 4.

https://github.com/toradex/debian-cross-toolchains

```
This repository has been incorporated into
[toradex/torizon-containers](https://github.com/toradex/torizon-containers).
```

Author: task-jp

docker/Dockerfile.torizon-demos

@@ -5,8 +5,9 @@
 
 ARG TOOLCHAIN_ARCH=arm64
 ARG IMAGE_ARCH=linux/arm64
+ARG BASE_VERSION=4
 ARG BASE_NAME=wayland-base
-FROM torizon/debian-cross-toolchain-$TOOLCHAIN_ARCH:3-bookworm AS build
+FROM torizon/cross-toolchain-$TOOLCHAIN_ARCH:${BASE_VERSION} AS build
 ARG TOOLCHAIN_ARCH
 ARG RUST_TOOLCHAIN_ARCH=aarch64-unknown-linux-gnu
 
@@ -43,7 +44,7 @@ RUN mkdir demos_compiled \
     done
 
 # Create container for target
-FROM --platform=$IMAGE_ARCH torizon/$BASE_NAME:3
+FROM --platform=${IMAGE_ARCH} torizon/${BASE_NAME}:${BASE_VERSION} AS deploy
 
 LABEL org.opencontainers.image.source=https://github.com/slint-ui/slint
 LABEL org.opencontainers.image.description="Container image providing Slint demos for use on Torizon. Run with docker run  --user=torizon -v /run/udev:/run/udev -v /dev:/dev -v /tmp:/tmp --device-cgroup-rule='c 199:* rmw' --device-cgroup-rule='c 226:* rmw' --device-cgroup-rule='c 13:* rmw' --device-cgroup-rule='c 4:* rmw'. Available demos: printerdemo slide_puzzle gallery opengl_underlay carousel todo"