Change `Regulatory considerations` to `Ethical Legal and Social Issues`

[bedroesb]

This will close #116 ans #72.

I took now section_elsi as page_id, is this ok? or do we go for the long one?

We might want to add the acronym in the description of the page.

WARNING: Merge this PR after #117 is merged

[bedroesb]

This time for real!