Windows-native implementations of services.

Currently external dependencies are used for functionality, which is pointless to implement manually:

• Libcrypto (OpenSSL) is used for cryptographic operations
• Libcurl is used for HTTP
• cJSON is used for parsing JSON.

This has been fluent as the same libraries have been used in all supported platforms.

The external dependencies however cause various complications in installation and building, which is why there should be native implementations on platforms, where the OS provides APIs for the required functionality.

The first implementation is on Windows: Use Windows APIs to perform HTTP and cryptographic operations.

This removes need for any external libraries and should help building and installing the client.