Launch chrome in headless mode so we don't need any GUI server anymore
Also open crhome in a fixed window size instead of maximazing it with some js.

Prepare integration to new CI

Move from npm to yarn.
This should make build system more robust.
To add/remove dependencies we must use yarn as foolow:
    yarn add __deps__ [--dev]

    yarn remove __deps_

Closes [BS-16656](https://bonitasoft.atlassian.net/browse/BS-16656)

Add npm start task to start dev mode.