update the roadmap for beta dev stage

> By @CarmenTamayo:
> * As a detail, the intro states that the topics covered by the tutorials are included in the diagram, however the "modelling interventions" doesn't appear on it. It says below that one or more episode will cover each topic, it would be ideal to have an expanded diagram of which episodes fit into which topic, and make sure that the names included there match the actual names of the episodes.

I understand your point, Currently, the roadmap diagram is a useful reference for package and tutorial development. Since we are in a [pre-alpha development](https://carpentries.github.io/lesson-development-training/lesson-design.html#iterative-development), we can probably keep the creation of episodes flexible, with no need to match the diagram yet. During this process, we may even split episodes if they take too much time to complete in a session or contain multiple goals that could be treated separately. Once we get to the next [alpha stage of development](https://carpentries.github.io/lesson-development-training/lesson-design.html#iterative-development) we should evaluate the stability of the episodes and update the roadmap diagram accordingly.

_Originally posted by @avallecam in https://github.com/epiverse-trace/tutorials/issues/59#issuecomment-1814647466_