Provide official language bindings for the OSV schema

[andrewpollock]

So we've got https://github.com/google/osv-scanner/blob/main/pkg/models/vulnerability.go evolving very nicely, however it's doing so in a not very friendly way towards downstream open source consumption.

It makes me think that this repo should host officially supported language bindings for all of the supported ecosystems that can be used as a dependency.