Implicit Configuration in .NET

In this latest development update from Vonage, they've taken the process of registering clients in their .NET SDK to the next level by introducing implicit configuration loading. This means that developers can now pass an IConfiguration instance directly to the `AddVonageClient` method, eliminating the need for manual initialization of credentials instances. Additionally, this update allows for environment-specific configuration, enabling developers to use different configurations for staging and production environments. With these changes, developers can simplify their interactions with the SDK and focus on writing code rather than managing configuration details.