Organise ~/milestones code

What does this MR do and why?

This MR organises ~/milestones code

• Rename ~/milestones/milestone_utils to ~/milestones/utils
• Move the following init* functions into ~/milestones/index.js
  • form.js
  • init_milestones_show.js
  • delete_milestone_modal_init.js
  • promote_milestone_modal_init.js

Screenshots or screen recordings

How to set up and validate locally

1. Test the milestones pages, http://127.0.0.1:3000/h5bp/html5-boilerplate/-/milestones etc

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.