Do set up a webserver config for web-based tests

[gggeek]

Check out the best way to set up a webserver:

• in the same container as ez or in a separate one?
• with/without varnish
• with/without https

Worst case scenario: use instead php's built-in one or the symfony-cli tool?

Also: make sure we allow the end user to specify custom routes and settings for security.yml.

[gggeek]

As corollary, we could allow to optionally run Selenium in a separate container :-D