Replace ObjectMapper (#67)

Use jms/serializer #35
Since a long time, jms/serializer is being able to deal with
interfaces the way we need and had other improvements such as
reading typed properties and doc blocks. There's no reason not
to use it anymore.

Author: marein

composer.json

@@ -25,6 +25,7 @@
     "doctrine/doctrine-migrations-bundle": "^3.0",
     "doctrine/orm": "^2.8",
     "enqueue/amqp-lib": "^0.10.8",
+    "jms/serializer": "^3.14",
     "marein/php-nchan-client": "^3.0",
     "marein/symfony-standard-headers-csrf-bundle": "^1.0",
     "predis/predis": "^1.1",
@@ -43,17 +44,17 @@
     "twig/twig": "^3.3"
   },
   "require-dev": {
-    "phpunit/phpunit": "^8.2",
-    "squizlabs/php_codesniffer": "^3.4",
+    "codeception/codeception": "^4.1",
+    "codeception/module-asserts": "^1.2",
+    "codeception/module-webdriver": "^1.1",
     "phpstan/phpstan": "^0.12.28",
-    "symfony/debug-bundle": "^5.1",
-    "symfony/web-profiler-bundle": "^5.1",
-    "symfony/stopwatch": "^5.1",
+    "phpunit/phpunit": "^8.2",
     "roave/security-advisories": "dev-master",
+    "squizlabs/php_codesniffer": "^3.6",
+    "symfony/debug-bundle": "^5.1",
     "symfony/error-handler": "^5.1",
-    "codeception/module-asserts": "^1.2",
-    "codeception/module-webdriver": "^1.1",
-    "codeception/codeception": "^4.1"
+    "symfony/stopwatch": "^5.1",
+    "symfony/web-profiler-bundle": "^5.1"
   },
   "config": {
     "sort-packages": true