Fix EZP-22318: Make Symfony session options SiteAccess aware

This patch allows to override session options at the SiteAccess level.
This includes:
* cookie_domain
* cookie_path
* cookie_lifetime
* cookie_secure
* cookie_httponly

Additionally, `session_name` setting is deprecated in favor of `session.name`:

Before:
```yaml
ezpublish:
    system:
        my_siteaccess:
            session_name: SomeSessionName
```

After:
```yaml
ezpublish:
    system:
        my_siteaccess:
            session:
                name: SomeSessionName
                cookie_path: /my_siteaccess
                cookie_httponly: true
```
EZP-22318: Tweaked fragment framework

Side effect when having a cookie path by SiteAcces (hence at runtime), when using a URI matcher, when you do an ESI or Hinclude,
you'll lose the SiteAccess part in the URI as the fragment path is configured per application, and not accessible at runtime.

Solution here is to ensure that the SiteAccess URI part is correctly reflected when generating the fragment path,
and to ensure the fragment listener accepts it.

As for the FragmentListener, a custom factory has been added to examinate the current pathinfo.
EZP-22318: Fixed tests
EZP-22318: Added tests
EZP-22318: Force legacy kernel to use Symfony session cookie settings

Depends on https://github.com/ezsystems/ezpublish-legacy/pull/881
Changed dependency on Symfony to 2.3.*

Problem is there is a BC break in Symfony 2.4 in fragment renderers.
A 4th argument "strict" was added in generateFragmentUri() method.
EZP-22318: Added specifications
EZP-22318: Clarified deprecated notes about session_name
Merge pull request #730 from ezsystems/impl_EZP-22318_sessionOptionsSiteAccess

Fix EZP-22318: Make Symfony session options SiteAccess aware