Changes

feat(scripts/ops/nextgen): add NextGen test failure statistics analyzer script (#3709)

This pull request introduces a new Deno-based script for analyzing
failed test cases from Jenkins JUnit reports and provides comprehensive
documentation for its usage. The script fetches test reports, extracts
error patterns, and outputs statistical summaries in various formats
with enhanced visual features. The most important changes are:

**New Script: Test Failure Statistics Analyzer**
* Added `statistics_failure_tests_from_junit_report.ts`, a Deno script
that fetches Jenkins JUnit JSON reports, analyzes failed test cases, and
generates error pattern statistics with options for text, JSON, and CSV
output. The script includes advanced error message extraction,
configurable filtering, verbose logging, and robust error handling.

**Documentation and Usage**
* Created a detailed `README.md` in `scripts/ops/nextgen/` describing
the script's features, installation steps, command-line options, output
formats, visual enhancements, error handling, and example usage
scenarios.
 (commit: 818634e)