ATLAS-5363: Atlas Documentation UI: REST API documentation styling broken on atlas.apache.org due to CSP violation

[Brijesh619]

What changes were proposed in this pull request?

This PR resolves ATLAS-5363 by fixing the broken styling on the Enunciate-generated REST API documentation caused by Content Security Policy (CSP) violations on atlas.apache.org.

Previously, the generated API docs loaded Bootstrap, jQuery, and prettify assets from external CDNs, which were blocked by the strict CSP rules on the Apache domain, resulting in unstyled pages.

This patch introduces the following changes:

• Adds local, static copies of the required frontend assets (bootstrap.min.css, bootstrap.min.js, jquery-1.12.2.min.js, and run_prettify.js) into webapp/src/main/enunciate-assets.
• Updates webapp/pom.xml to copy these local assets into the generated Enunciate documentation output directories (target/api/v2/ and target/api/v2/apidocs/ui/) during the build.
• Adds an Ant <replace> task in the build process to scan the generated Enunciate HTML files and swap out the external CDN URLs for local, relative paths pointing to the bundled CSS/JS files.

How was this patch tested?

• Manual Build Testing: Ran mvn clean package and verified that the enunciate-assets are correctly copied into webapp/target/api/v2/ and its subdirectories.
• HTML Verification: Inspected the generated index.html and verified that the CDN links were successfully replaced with relative paths (e.g., href="css/bootstrap.min.css" and src="js/jquery-1.12.2.min.js").
• Local Browser Testing: Served the generated webapp/target/api/v2/apidocs/ directory locally and verified in the browser that the styling, layout, and JavaScript formatting (run_prettify) load properly without any CSP errors in the browser console.