Add type tests with an adapted version of JSONSchema validator in FQL

[gahabeen]

Summary

Idea is to be able to validate inputs/ouputs like GraphQL would do.
It needs an adapted JSON Schema validator in plain FQL.
It would allow to test anything passed around in biota and make sure everything's stricly typed (and nothing goes south).
It would allow to set schemas for collections for example (again, like GraphQL does).

Basic example

Motivation