feat(bqjdbc): Per connection logs - Add BigQueryJdbcMdc

[Neenu1995]

PR 1 of Per connection logging implementation.

• Implements BigQueryJdbcMdc using an InheritableThreadLocal design and corresponding unit tests for verification.
• Use DateTimeFormatter instead of SimpleDateFormat for better performance.

[gemini-code-assist]

Code Review

This pull request introduces a lightweight MDC implementation for the BigQuery JDBC driver to track connection IDs and updates the logging formatter to use modern java.time APIs. The review feedback identifies several critical issues in the new BigQueryJdbcMdc class, including potential memory leaks from static maps holding connection references, thread-safety bugs in the clear() method, and performance inefficiencies caused by redundant InheritableThreadLocal instances. Suggestions were also provided to refine the connection removal logic and ensure side-effect-free mapping functions.