adding automatic handling of vaccine age restrictions

[rjkerrison]

I accidentally booked a Moderna vaccine not knowing I was underage for it. To save others from making the same error (and potentially wasting doses), I've added support to automatically reflect those restrictions.

At time of writing, ameli.fr's Qui peut se faire vacciner, quand et comment? states that:

• "Le vaccin Moderna n'est cependant ouvert qu'aux personnes âgées de 30 ans et plus."
• "Les adolescents âgés de 12 à 17 ans peuvent se faire vacciner contre le Covid-19 avec le vaccin Pfizer." 

[rbignon]

Hello,

Thank you for your contribution. It seems nice, but I don't know if these rules apply in Germany. If not, perhaps it would be better to exclude vaccines only if they are not specified explicitly?