Add build tools

[nielslange]

Fixes #12

Add build tools to generate CSS and translations files.

Screenshots

n/a

How to test the changes in this Pull Request:

1. Check out this PR
2. Run npm i to install all dependencies → Dependencies should be installed
3. Run npm run build to build the extension → The file storefront-hamburger-menu.zip should be created in root
4. Run npm run build:dev to render JS and SCSS files → The files assets/css/style.css, assets/css/style.css.map, assets/css/style.min.css, assets/js/customizer.js, assets/js/customizer.min.js & assets/js/customizer.min.js.map will be rendered
5. Run npm run start to watch SCSS changes → If src/css/style.scss will be changes, the files assets/css/style.css, assets/css/style.css.map & assets/css/style.min.css will be rendered
6. Run npm run watch to watch SCSS changes → If src/css/style.scss will be changes, the files assets/css/style.css, assets/css/style.css.map & assets/css/style.min.css will be rendered
7. Run npm run js to render JS files → The files assets/js/customizer.js, assets/js/customizer.min.js & assets/js/customizer.min.js.map will be rendered
8. Run npm run css to render SCSS files → The files assets/css/style.css, assets/css/style.css.map & assets/css/style.min.css will be rendered
9. Run npm run makepot to render the POT file → The file languages/storefront-hamburger-menu.pot will be rendered

Changelog

Dev - Add build tools to generate CSS and translations files. #12

Tests

• I've tested browser support to ensure compatibility with >= IE11
• I've tested using only a keyboard (no mouse)
• I've tested using a screen reader
• All animations respect prefers-reduced-motion
• All text has at least a 4.5 color contrast with its background

Note

The initial PR #16 had accidentally been closed when renaming the primary branch from master to trunk. I simply grabbed the relevant changes of the initial PR and opened this new PR to add the build tools to this repo.