Feature: Update C# API for v4.0

[anafro]

Is your feature request related to a problem? Please describe.
The Quark Server went into oblivion, and Quark Cloud went onto the stage! It's time to update the API for Quark 4.0!

Describe the solution you'd like
Read the API documentation in the main Quark's repo, and update the C# API.
Also publish it to NuGet.