[FEATURE] Amazon Bedrock Cohere Rerank 3.5 pre/post process function functionality

[mateon01]

Is your feature request related to a problem?
In order to use the coherent rerank model with Bedrock, we need to write a separate script as the existing function does not work. It's in the tutorial, but it's complicated and we need to make it a built-in function within the plugin.

What solution would you like?
Built-in functions make it easier to use the Amazon Bedrock Cohere Rerank model.

What alternatives have you considered?
None

Do you have any additional context?
None