Refactor APIClient to use Decodable objects or any other generic approach

[glm4]

Currently, the APIClient class tries to parse a dictionary using JSONSerialization, this brings a couple of problems:

1. single elements or Arrays from a JSON response are not be supported.
2. The dictionary is then used to convert it into a Data object to then use a JSONDecoder. This is an unnecessary back and forth which adds complexity and more prone to errors.

Ideally, the client would pass a type that would like to get back and the APIClient will handle the rest. An alternativeis to ahve like a middle layer that takes care of the parsing/decoding.