Add encryption support for nested dicts and lists

[jcarlosdev]

• Added new field definition classes for complex types
• Complex types refer to dictionaries, lists nested into dictionaries, lists, lists of dictionaries and primitive types, both top-level and with any level of nesting
• NestedEncryptedField can be used to define field level encryption on nested complex types for schemas that inherit from the Document class
• NestedEncryptedProperty can be used to define field level encryption on nested complex types for schemas that inherit from the MappedClass class
• Updated encryption functions to support dictionaries and lists.
• Added test coverage for the new encrypted types