add structure to the summary page from announcement page

Thank you for your comments. I'll reply to them citing each point. When needed, I'll create new issues with the "Reference in new issue" option to solve them isolated.

> By @CarmenTamayo:
> * Who is the intended audience? The 3 examples of learning personas is okay, but I wouldn't only provide that, I think it's important to first spell out clearly what the pre-requisites and target audience is, and then maybe exemplify this with the learning personas. Otherwise it might be confusing, as most people are not going to be represented by these 3 hypothetical people.

We can adapt the announcement page we prepared for the design of this material ([reference](https://epiverse-trace.github.io/lessons/about.html)).

Add info on:
- What will you learn? but expanded as general learning objectives (as in [this reference](https://epiverse-trace.github.io/learn/git-training-01/#what-will-you-learn))
- Who are these lessons for? with the learner personas.
- What is not included in this material? to help the learner decide if this is the correct material to consume or redirect them to others. here we can [re-write the related projects section.](https://epiverse-trace.github.io/tutorials/#related-projects)

_Originally posted by @avallecam in https://github.com/epiverse-trace/tutorials/issues/59#issuecomment-1814420388_