FAQ on OpenVEX

[sparrell]

Draft an FAQ on how information modelling relates to OpenVex.

It is possible, likely even, that this will require a full Committee Note and not be able to be complete until after we have at least a draft of the VEX Information Model Committee Specification. But showing the infomation model vs the data model and drafting the FAQ (and discussing it) will help flesh out what work we need to do in