Sdg23 refine 'learning MDAnalysis' page

[namiroues]

This PR addresses #441.

[orbeckst]

Looks good from my view.

As commented, I'd still mention the papers somewhere.

(And I agree with @micaela-matta to include workshop materials somewhere but I assume you'll address that comment.)

[orbeckst]

@namiroues @micaela-matta have you discussed who is going to eventually merge the PR?

I am asking because @namiroues is assigned to the PR. In the main repo we typically assign the PR to the person who is overseeing review and merging, so I wasn't sure how you wanted to handle it here.

[namiroues]

@namiroues @micaela-matta have you discussed who is going to eventually merge the PR?

I am asking because @namiroues is assigned to the PR. In the main repo we typically assign the PR to the person who is overseeing review and merging, so I wasn't sure how you wanted to handle it here.

Thanks @orbeckst for the clarification. I unassigned myself from the PR.

[namiroues]

Thanks @orbeckst and @micaela-matta for your comments. I restructured the page a bit and look forward to hearing your feedback. :)

Just a comment: The "Tutorials repository" link is missing until this is cleared. This goes on the TODO list.