Clarify point about multiple database versions

https://gitlab.cta-observatory.org/cta-computing/dpps/simulationpipeline/roadmap-and-implementation/-/blame/seps/enhancement-proposals/sep-0001.md?ref_type=heads#L63

In the warning above, the point about multiple database versions should be clarified. I assume you mean multiple databases, each one for a specific version of the production model (or something like that). I would also list what is the advantage of that exactly (cause I am not sure I see it).