feat: add the option to configure a proxy for the HTTP client

[JonasDevDE]

This pull request introduces support for configuring an HTTP proxy in the ApiClient class. The changes enable users to specify a proxy via the HttpOptions class, which is then used when creating the HTTP client. Below is a breakdown of the most important changes:

Proxy Support in HTTP Client:

• ApiClient.java:

  • Added imports for Proxy, SocketAddress, and InetSocketAddress to facilitate proxy configuration.
  • Updated the createHttpClient method to use the proxy configuration from HttpOptions if provided.

• HttpOptions.java:

  • Added a new proxy property to the HttpOptions class to store optional proxy configurations.
  • Updated the builder for HttpOptions to include a setter for the new proxy property.

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