Determinate inclusion metadata on existence method meta

Changes:
1. If :add_metadata option not provided determine add metadata or not
    by existence method meta in model serializaer class.
2. Remove api version methods -> use demodulize & deconstantize from active_support/inflector
3. Remove some attributes from collection serializer class
    (which are just transferred to model serializer class).
4. Remove _api_version argument from resolve_serializer mehod which was not used in that method.