UX - Activate dev mode from wizard

GOAL
Make base dev experience smoother for people trying nuxeo platform.
Currently people need to activate dev mode manually by editing nuxeo.conf in order to use hot reload, and it's totally counter intuitive.
=> we want to integrate this by default in the wizard

TODO
Produce mockups for feature integration

Acceptance Criteria

• When wizard is launched, a new option shows up to activate / deactivate dev mode
• Message shows:

  Dev mode allows you to hot reload configuration made using Nuxeo Studio in seconds, without having to restart your server. Disable it if you intend to use this instance for production.

• Dev mode is activated by default
• nuxeo.conf reflects the selection made in the wizard when starting the server after wizard is finished