Migrate JavaScript and Stylesheets to esbuild

[marcoroth]

This pull request includes several changes to update the JavaScript bundling and build process, as well as some related configuration updates. The main changes involve switching from Webpacker to jsbundling-rails and updating Node.js and various configuration files accordingly.

JavaScript Bundling and Build Process Updates:

• Gemfile: Replaced webpacker with jsbundling-rails for JavaScript bundling.
• Procfile.dev: Updated the JavaScript build command to use yarn build --watch instead of bin/webpack-dev-server.
• app/views/layouts/application.html.erb: Replaced javascript_pack_tag and stylesheet_pack_tag with javascript_include_tag for loading JavaScript and CSS.

Node.js and Configuration Updates:

• .node-version: Updated Node.js version from 16.15.0 to 22.11.0.
• README.md: Updated references from Webpacker and Node 16 to jsbundling-rails and Node 22.

Asset and Stylesheet Management:

• app/assets/config/manifest.js: Updated to link the ../builds directory instead of ../stylesheets.
• app/assets/stylesheets/application.css: Removed the old stylesheet manifest file.
• app/javascript/stylesheets/_bootstrap.scss: Added custom Bootstrap variables and imported Bootstrap.
• app/javascript/stylesheets/application.scss: Moved styles and imports from the removed application.css file.

JavaScript File Updates:

• app/javascript/application.js: Added imports for configuration, channels, controllers, and stylesheets.
• app/javascript/channels/index.js: Updated to use ES6 import syntax for loading channel files.
• app/javascript/controllers/index.js: Updated to use ES6 import syntax for loading controller files.

Removal of Webpacker Configuration:

• Removed Webpacker configuration files including config/webpack/development.js, config/webpack/environment.js, config/webpack/production.js, config/webpack/test.js, and config/webpacker.yml. [1] [2] [3] [4] [5]