Activate dev mode from wizard

GOAL
Make base dev experience smoother for people trying nuxeo platform.

Currently, to activate dev mode and start working on Studio, you have to:

• Go through wizard => start nuxeo => find that you need to edit nuxeo.conf to do hot reload => find nuxeo.conf => activate dev mode => restart => launch hot reload
  It would be a much better UX to allow activating dev mode during wizard to have the following flow:
• Go through wizard and activate dev mode => start nuxeo => launch hot reload

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