Enhance StartJenkinsJob plugin documentation

Updated the StartJenkinsJob plugin description to emphasize reliability and support for dynamic input fields. Expanded the QA section with new questions on best practices and error handling. Added examples for custom polling intervals, parameterized jobs, and data extraction using JSONPath and Regex. Revised output parameters for clarity and reorganized the parameters section with detailed descriptions and new default values. Introduced RegularExpression and OnElement properties for data extraction. Rewritten summary to highlight plugin capabilities in automation workflows.

Author: gravity-api