DC: migrate from Bootstrap + Webpack to Tailwind + ESbuild

[conradwt]

• remove webpack.config.js
• remove package.json
• remove package-lock.json
• remove .babelrc
• remove node_modules
• install and configure EsBuild
• install and configure DartSass
• install and configure Tailwind

References:

• https://tailwindcss.com/docs/guides/phoenix
• https://pragmaticstudio.com/tutorials/adding-tailwind-css-to-phoenix
• https://www.wiserfirst.com/blog/upgrade-to-phoenix-16