Add type namespaces for Schema

[tshemsedinov]

• Collection of models Schema.prototype.namespaces: Set<Model>
• Add Schema constructor argiment: (name, raw, namespaces: Array<Model>)
• Add model(s) to allow references Schema.prototype.attach(...args: Array<Model>)
• Remove model(s) Schema.prototype.detouch(...args: Array<Model>)