Vaccine cards for AZD2816 and mRNA-1273(B.1.351)

[KaimingTao]

Do not create the database-related issue here. Please go to https://github.com/hivdb/covid-drdb/issues.

[philiptzou]

What's the problem with mRNA-1273? Related file needs to be updated: https://github.com/hivdb/chiro-cms/blob/master/resources/vaccine-description.yml