Api alignment

[DariusIMP]

• Removed all the resolvables and all the builder patterns. Using default arguments instead.
• Converted a couple of classes into 'data' classes.
• Selector: fix using empty string for parameters, now using optional string.
• Removing the Attachment class, and passing instead a ZBytes instance.
• Implementation of the ZBytes class
• Implementation of the serialization & deserialization logic
  • Serialization for:
    • Numeric types
    • String type
    • ByteArray type
    • List, where T is one of the raw types mentioned, or can be a custom class implementing the Serializable interface.
    • Map<T, T>, where T is again, one of the raw types mentioned or types implementing the Serializable interface.
  • Deserialization for:
    • Numeric types
    • String type
    • ByteArray type
    • List, where T is one of the raw types mentioned, or can be a custom class implementing the Deserializable interface.
    • Map<T, T>, where T is again, one of the raw types mentioned or types implementing the Deserializable interface.
  • Added some ZBytes tests
  • Added a ZBytes example.