EZP-31007: Replaced ezpublish-kernel with ezplatform-kernel (#27)

* EZP-31007: [Composer] Replaced ezpublish-kernel with ezplatform-kernel

* [Composer] Installed required dev dependencies

  Dependencies were needed to resolve minimum stability requirements of Composer

composer.json

@@ -14,7 +14,7 @@
         }
     ],
     "require": {
-        "ezsystems/ezpublish-kernel": "^8.0@dev",
+        "ezsystems/ezplatform-kernel": "^1.0@dev",
         "twig/twig": "^3.0",
         "symfony/dependency-injection": "^5.0",
         "symfony/http-kernel": "^5.0",
@@ -26,6 +26,7 @@
         "symfony/templating": "^5.0"
     },
     "require-dev": {
+        "ezsystems/doctrine-dbal-schema": "^1.0@dev",
         "phpunit/phpunit": "^8.1",
         "friendsofphp/php-cs-fixer": "~2.15.3",
         "mikey179/vfsstream": "^1.6"