EZP-21118: Implemented CORS support for the REST API

Uses NelmioCorsBundle.
Fix EZP-22101: Tweaked DefaultRouter param loading

The configResolver was used too early in a condition,
and was instanciating the legacy DB too early.
EZP-21118: Fixed EventListener test
EZP-22133: Removed final keyword on sudo() function

To be proxy-able, public functions must be extendable. final keyword prevents that.
Merge branch 'master' into story/EZP-21118-HTTP_CORS

Conflicts:
	composer.json
Merge branch 'story/EZP-21118-HTTP_CORS'
EZP-22133: Fixed tests
Merge pull request #673 from ezsystems/fix_EZP-22133_sudoNotWorking

EZP-22133: sudo not working with lazy repository
EZP-22051: Implemented base preview mechanism
EZP-22051: Forward request directly to the ViewController instead of dealing with the ViewManager
EZP-22051: Made ViewControllerListener aware of « location » and « contentInfo » request attributes
EZP-22051: Matcher factories: if siteaccess is null, don’t do anything + added tests
EZP-22051: Correctly inject locationId/contentId in request attributes when ViewControllerListener matches a Location or ContentInfo object
EZP-22051: Made it possible to pass a Location object in $params in ViewController
EZP-22051: Made it possible to directly pass Content object in ViewManager::renderLocation()
Removed useless @covers in ViewManagerTest
EZP-22051: Refactored PreviewController
EZP-22051: Added new tests for core ConfigResolver
EZP-22051: Added tests for core PreviewController
EZP-22051: Added isPreview