Persistent using localStorage since container width should be per device

- Use PostCSS instead of Less plugin
- Fixes CSS append problem
- Show which css file changed instead of rollup.manifest.css
- Minify CSS in production
- Cannot import less/css files in js files, put them in build.json
- Let's avoid major changes in Frappe Framework now :)

* Better rollup messages in console

* Remove 'docs folder not found' warning

* Show production message

* fix codacy

* JS build working

* Css build working!

* Uglify JS in production

* fix codacy

* Add frappe.commands.popen

* FIx ESLint errors

* Add socket.io to package.json

* ignore subprocess warnings

* Add babel-runtime

* sleep 20 after bench start

* remove set -e

* [FIX] non-shell subprocess call

* [FIX] use shell = False

* split commands