[FEATURE] Support for passing the PoolingHttpClientConnectionManager as a dependency

[stikkireddy]

Problem Statement For model serving with optimized routes we need to be able to send significantly larger volume of concurrent requests. it would be great to be able to control the pooling config.

Proposed Solution Pass the pooling config as part of the setting the databricks config.

Additional Context Alternative is to maintain a custom http client implementation with custom pooling manager configurations.