feat: Add Modern JavaScript Patterns for Client Scripts

[ashvin2005]

• Add async GlideAjax patterns with promise-based implementations
• Add ES6 field management techniques using modern syntax
• Add promise-based operations for better asynchronous handling
• Include comprehensive documentation and usage examples

These patterns demonstrate modern JavaScript techniques in ServiceNow:

• Async/await patterns for GlideAjax calls
• ES6+ syntax for cleaner, more maintainable code
• Promise-based operations for better error handling
• Modern client-side development practices

PR Description:

replace this with your description

Pull Request Checklist

Overview

• Put an x inside of the square brackets to check each item.
• I have read and understood the CONTRIBUTING.md guidelines
• My pull request has a descriptive title that accurately reflects the changes and the description has been filled in above.
• I've included only files relevant to the changes described in the PR title and description
• I've created a new branch in my forked repository for this contribution

Code Quality

• My code is relevant to ServiceNow developers
• My code snippets expand meaningfully on official ServiceNow documentation (if applicable)
• I've disclosed use of ES2021 features (if applicable)
• I've tested my code snippets in a ServiceNow environment (where possible)

Repository Structure Compliance

• I've placed my code snippet(s) in one of the required top-level categories:
  • Core ServiceNow APIs/
  • Server-Side Components/
  • Client-Side Components/
  • Modern Development/
  • Integration/
  • Specialized Areas/
• I've used appropriate sub-categories within the top-level categories
• Each code snippet has its own folder with a descriptive name

Documentation

• I've included a README.md file for each code snippet
• The README.md includes:
  • Description of the code snippet functionality
  • Usage instructions or examples
  • Any prerequisites or dependencies
  • (Optional) Screenshots or diagrams if helpful

Restrictions

• My PR does not include XML exports of ServiceNow records
• My PR does not contain sensitive information (passwords, API keys, tokens)
• My PR does not include changes that fall outside the described scope

[ravichandra1998g]

Hello @ashvin2005

The submitted files contain hundreds of lines of code with multiple functions, which makes them difficult to understand even with documentation.

Please organize and submit smaller code snippets for specific use cases under dedicated folders (e.g., Catalog Client Script, UI actions, Business Rule, etc.) along with a clear README file explaining the use case and the purpose of each script.

The current code is not ideal for code snippet submissions and make it harder to reuse the code effectively.