Switch to node:20-alpine container base image

[lkiesow]

This patch switches to the node alpine container which is significantly smaller than the Debian based container we use now:

docker.io/library/node                      20-alpine    91247b4bc29d  3 days ago     135 MB
docker.io/library/node                      20-bookworm  4c466ea4074f  9 days ago     1.12 GB
docker.io/library/node                      20           4c466ea4074f  9 days ago     1.12 GB

This results in significantly smaller test containers:

opencast-admin-interface          node-20-alpine  c9b84375017f  13 seconds ago      700 MB
opencast-admin-interface          node-20         2decf3414d30  About a minute ago  1.68 GB

[github-actions]

This pull request is deployed at test.admin-interface.opencast.org/681/2024-06-07_19-16-43/ .
It might take a few minutes for it to become available.

[github-actions]

Use docker or podman to test this pull request locally.

Run test server using develop.opencast.org as backend:

podman run --rm -it -p 127.0.0.1:3000:3000 ghcr.io/opencast/opencast-admin-interface:pr-681

Specify a different backend like stable.opencast.org:

podman run --rm -it -p 127.0.0.1:3000:3000 -e PROXY_TARGET=https://stable.opencast.org ghcr.io/opencast/opencast-admin-interface:pr-681

It may take a few seconds for the interface to spin up.
It will then be available at http://127.0.0.1:3000.
For more options you can pass on to the proxy, take a look at the README.md.

[Arnei]

Sure, let's try it out.