Defining schemas, fields and field types

Initial interface implementation of:
- IObject - everything in Atomic is inheritable from IObject
- ISchema - defines a schema, structured by it's collection of fields
- IField - defines a field that can be as part of a schema
- IFieldType - defines a type of field
Revert "Defining schemas, fields and field types"

This reverts commit a87704d0cc7d542326d041dc8726a953e17eaeeb.
First look at how to structure documents