entity person: create a validator to check a person entity is linked

with a center

This validator take a parameter in configuration

src/Bundle/ChillPersonBundle/Validator/Constraints/Person/PersonHasCenter.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Chill\PersonBundle\Validator\Constraints\Person;
+
+class PersonHasCenter extends \Symfony\Component\Validator\Constraint
+{
+    public string $message = "A center is required";
+
+    public function getTargets()
+    {
+        return [
+            self::CLASS_CONSTRAINT
+        ];
+    }
+}