Add SSL credentials support for secure gRPC channels

[AlphaKhaw]

Description

This PR adds native support for secure gRPC channels in the ImmuDB Python client by introducing an optional ssl_credentials parameter to the ImmudbClient constructor.

Changes

• Added ssl_credentials parameter to ImmudbClient.__init__
• Modified channel creation logic to support both secure and insecure channels
• Updated documentation to reflect new parameter
• Maintained backward compatibility with existing implementations

Example Usage

Create secure channel

credentials = grpc.ssl_channel_credentials()
client = ImmudbClient(immudUrl="host:port", ssl_credentials=credentials)

Existing usage remains unchanged

client = ImmudbClient(immudUrl="host:port") # Creates insecure channel

Related Issue

Closes #79

Testing

• Tested with both secure and insecure connections
• Verified backward compatibility
• Tested with production ALB setup

Documentation

Updated docstring in ImmudbClient.__init__ to document the new parameter.