Fixes #14688 - Power status visible on hosts index page

Fixes #13936 - Drop support for legacy browsers

This patch removes various workarounds needed to get legacy browsers to
work. Mostly stuff needed for IE<10, but also some other vendor prefixes
that are no longer needed.

Fixes #16120 - Allow including css in webpack assets

This commit demonstrates using the css from the select2 module using the
webpack css loaders. Images under 32k will be compiled into the css to
reduce request counts.

Fixes #16075 - add authenticity token in setting params

Fixes #12364 - Use NPM+Webpack to handle external assets

This commit introduces NPM and Webpack to handle external assets.
It also provides ES6 support and a live reload dev server that can be
used by running `foreman start` instead of `rails start`.
Do not forget to run `npm install` before starting the server....

Fixes #8797 - Separate style from the HTML in emails

By using roadie-rails gem (1.1) style can be separated from email
html foramt, and absolute paths can be used.
style was separated to 'email.css'

fixes #14318 - load JS translations table for current locale only

Fixes #13235 - content from application layout extracted into a partial

Fixes #9480 - multiple NICs integration with compute profiles

From users point of view:
- interfaces setup in compute profiles is back
- interface related compute attrs get merged into host NICs upon compute
profile selection
- NIC overview table displays details in the column "Type"...

fixes #8802 - add Turbolinks support