Fixes #16293 - Move vendored diff.js to webpack (#3784)

Also removed a few outdated lines from the LICENSE file.

Fixes #13047, #16291 - Upgrade datatables and move it to npm

fixes #16089 - replace flot-rails with npm jquery-flot

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 #15829 - remove ace-rails-ap file modes from app.js

Also removes editor from precompilation list, it's in the main app.js
since fa8353d, and removes unused ACE extensions.

application.js has reduced from 2512 to 2381KiB.

Fixes #15037 - Improves editable elements in settings

Fixes #15140 - Correctly handle failed setting change

The jEditable library contains a bug that causes any failed changes to
settings to break the layout of the setting input in following changes.
Since the library is not maintained any more, we had to change our copy...

Fixes #15137 - Find correct jnotify container

jnotify creates message container on first use and caches it
internally. When using turbolinks, page body is swapped
but jnotify has no clue about the change and appends the
message to the old container which means no message is...

Fixes #13741 - Prevent hidden parameters from erasing newline

Switching the input from textarea to password leads to all newline
characters being stripped from the value. This PR attempts to prevent
this by changing the font of the textarea to a font that displays a...

Fixes #4629 - Migrate UI to Patternfly