Simplify development approach

[gtvj]

This PR is to simplify the development approach by:

• [x] Removing Parcel.js as an unnecessary development dependency
• [x] Removing Node as a project dependency
• [x] Introducing SASS as a global package, and having a watch task which has no dependency on a build system (such as Grunt)
• [x] Removes unnecessary JavaScript file
• [x] Removes unnecessary grid.html file