fix/EZP-21207 Creating a view with the wrong schema must return an error 400 instead of error 500
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
EZP-22210: Added specifications for legacy bundles
EZP-22210: Added LegacyBundleInstallCommand.php
EZP-22210: Added legacy extensions locator

Ignored bundles without ezpublish_legacy folder
EZP-22210: Inplemented compiler pass + legacy mapper
EZP-22210: Added LegacyBundles config mapper

The Container parameter ezpublish_legacy.legacy_bundles_extensions,
filled in by the compiler pass, is injected into the mapper
to be injected into legacy.
EZP-22210: Removed LegacyBundleExtension interface
EZP-22210: Changed injection to use merge-settings
EZP-22210: Fixed locator algorithm
EZP-22210: Re-introduced LegacyBundleInterface

Bundles may implement eZ\Bundle\EzPublishLegacyBundle\LegacyBundles\LegacyBundleInterface,
and return an arbitrary list of legacy extensions that must be enabled in the legacy kernel.
Fix EZP-22353: Travis database error on ezpublish-community
EZP-22210: Updated and improved spec