composer.json: renommage package Composer + suppression clé repositories inutile.

composer.json

 {
-  "name": "unicaen/unicaen-ldap",
-  "description": "Module Ldap de l'UCBN",
-  "repositories": [
-    {
-      "type": "composer",
-      "url": "https://dev.unicaen.fr/packagist"
-    }
-  ],
+  "name": "unicaen/ldap",
+  "description": "Module Ldap des applications Unicaen",
   "require": {
     "php":                                  "^5.6 || ^7.0",
     "zendframework/zend-servicemanager":    "~2.4 || ^2.7",