http - implement body inspection handler

[baywet]

specification microsoftgraph/msgraph-sdk-design#116
make sure you update the documentation as well

[Nikk8091]

Hi, I would like to work on this issue.\n\nI plan to implement the HTTP body inspection handler for Kiota Java following the linked middleware specification and the existing Kiota .NET behavior, add focused tests for request and response body inspection, and update the middleware documentation.\n\nI will keep the change scoped to this handler and share the validation results in the pull request. Thank you!