Docs: Mention other upload tools next to python for images.

[underdarknl]

          If we can install python we can install Curl, but for now this is fine. Lets just keep the docs as simple as possible and at least mention the possibility of using tools like wget, curl or another http client.

Originally posted by @underdarknl in https://github.com/minvws/nl-kat-coordination/pull/2827#discussion_r1584415894