Add generation of model/collection information/OpenAPI specs

[morrisjdev]

To make development of client applications easier, without knowing the server-code it would be helpful to provide information about the current models and collections on server side.

An interface that provides OpenAPI spec-files would work, but a few adjustments would be neccesary.
It is not possible to generate model specs without a REST-Interface returning this model.
Maybe a fork of one of the .NET swagger libraries is a solution.

Ideas and suggestions welcome.