Cleanup CSS and JS files, update dependencies

[thejspr]

My previous PR, broke the deployment script. Fixing this issue took me down a path, removing a lot of unnecessary dependencies and build steps:

• Removed a bunch of unused CSS
• Removed Gulp-based asset processing, which is now done by Hugo
• Removed unused icons and fonts from being loaded

[Copilot]

Pull Request Overview

This PR removes unused assets and simplifies the build process by migrating from Gulp-based asset processing to Hugo's native asset handling, fixing a deployment issue from the previous PR.

• Removed external font and icon dependencies from Google Fonts and Material Design Icons CDN
• Simplified build process by eliminating Gulp asset processing tasks and related dependencies
• Updated jQuery version and migrated JavaScript handling to Hugo's asset pipeline with fingerprinting

Reviewed Changes

Copilot reviewed 12 out of 26 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
website/layouts/partials/header.html	Removed external font and icon stylesheet links
website/layouts/partials/footer.html	Updated jQuery version and migrated JS to Hugo asset pipeline
website/layouts/partials/docshero.html	Removed entire hero section partial
website/layouts/index.html	Added missing closing HTML tags
website/layouts/404.html	Changed text color from dark to white
website/assets/js/main.js	Removed leading empty line
website/assets/css/main.css	Removed unused merchant-icon CSS rule
website/assets/css/docs.css	Removed extensive unused CSS for API categories, navigation, and mobile components
package.json	Removed Babel, auth0, and other unused dependencies; updated version
gulpfile.js	Removed asset processing functions, kept only Hugo build and deploy tasks
babel.config.js	Deleted entire Babel configuration file
.github/workflows/deploy.yml	Updated checkout action from v3 to v4

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