Feature: Support for custom TLS configuration

[RequiemP]

Currently, the Qdrant client uses default TLS settings (like native roots) when connecting over HTTPS. Users operating in environments with specific security requirements, such as those using custom CAs, cannot configure the client's TLS handshake process.

I've implemented a solution that adds an optional tls_config field to QdrantConfig, allowing users to provide their own tonic::transport::ClientTlsConfig for fine-grained control over TLS settings: #271