Add ability to define created_at for all import

At the moment only Readability & wallabag v2 import allow created_at import.
Pocket removed `time_added` field from their API v2 to v3...
And wallabag v1 doesn't export that value.

src/Wallabag/ImportBundle/Import/PocketImport.php

@@ -193,6 +193,11 @@ class PocketImport extends AbstractImport
         $this->client = $client;
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @see https://getpocket.com/developer/docs/v3/retrieve
+     */
     public function parseEntry(array $importedEntry)
     {
         $url = isset($importedEntry['resolved_url']) && $importedEntry['resolved_url'] != '' ? $importedEntry['resolved_url'] : $importedEntry['given_url'];

src/Wallabag/ImportBundle/Import/ReadabilityImport.php

@@ -89,6 +89,9 @@ class ReadabilityImport extends AbstractImport
         return true;
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function parseEntry(array $importedEntry)
     {
         $existingEntry = $this->em
@@ -108,6 +111,7 @@ class ReadabilityImport extends AbstractImport
             'language' => '',
             'is_archived' => $importedEntry['archive'] || $this->markAsRead,
             'is_starred' => $importedEntry['favorite'],
+            'created_at' => $importedEntry['date_added'],
         ];
 
         $entry = $this->fetchContent(
@@ -125,6 +129,7 @@ class ReadabilityImport extends AbstractImport
 
         $entry->setArchived($data['is_archived']);
         $entry->setStarred($data['is_starred']);
+        $entry->setCreatedAt(new \DateTime($data['created_at']));
 
         $this->em->persist($entry);
         ++$this->importedEntries;

src/Wallabag/ImportBundle/Import/WallabagImport.php

@@ -139,6 +139,10 @@ abstract class WallabagImport extends AbstractImport
         $entry->setArchived($data['is_archived']);
         $entry->setStarred($data['is_starred']);
 
+        if (!empty($data['created_at'])) {
+            $entry->setCreatedAt(new \DateTime($data['created_at']));
+        }
+
         $this->em->persist($entry);
         ++$this->importedEntries;
 

src/Wallabag/ImportBundle/Import/WallabagV1Import.php

@@ -42,6 +42,7 @@ class WallabagV1Import extends WallabagImport
             'is_archived' => $entry['is_read'] || $this->markAsRead,
             'is_starred' => $entry['is_fav'],
             'tags' => '',
+            'created_at' => '',
         ];
 
         // force content to be refreshed in case on bad fetch in the v1 installation