Add support for pfizer for kids (5 to 11yo)

[douardda]

Unless I missed it, I do not see how to use doctoshotgun to book a vaccine slot for a kid (5 to 11yo) in France.

I'd be happy to send a PR, but I'm not sure how to retrive the code for this specific vaccine (to add in DoctolibFR).

[scandel]

When you choose the type of vaccine (here pediatric):

It translates into a "visit motive", here 10515 (https://www.doctolib.fr/vaccination-covid-19/paris?ref_visit_motive_ids[]=10515)