[SECURITY] Fix Log4Shell CVE-2021-44228

Critical Security Fix

This MR addresses CVE-2021-44228 (Log4Shell), a critical JNDI injection vulnerability in Apache Log4j 2.x.

Vulnerability Details

• CVSS Score: 10.0 (Critical)
• Attack Vector: Network
• Impact: Remote Code Execution
• Affected Version: log4j 2.14.1

Changes

• Upgraded log4j2.version from 2.14.1 to 2.17.1
• Removes JNDI lookup functionality
• Patches all known attack vectors

Testing

• ✅ Unit tests pass
• ✅ SAST scan clean
• ✅ Dependency scan shows no critical vulnerabilities

Closes #2 (closed)

fixes https://gitlab-knowledge-graph.michaelangelo.io/acme-corp/java-microservices/user-service/-/security/vulnerabilities/4

cc: @bill_staples @michael_usanchenko