Move to Symfony Flex

The structure changed completely.
Bundles are gone. Everything is flatten in the folder `src`.
I separated import & api controllers to avoid _pollution_ in the main controller folder.

migrations/Version20190708122957.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace DoctrineMigrations;
+
+use App\Doctrine\WallabagMigration;
+use Doctrine\DBAL\Schema\Schema;
+
+/**
+ * Change reading speed value.
+ */
+final class Version20190708122957 extends WallabagMigration
+{
+    public function up(Schema $schema): void
+    {
+        $this->addSql('UPDATE ' . $this->getTable('config', true) . ' SET reading_speed = reading_speed*200');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('UPDATE ' . $this->getTable('config', true) . ' SET reading_speed = reading_speed/200');
+    }
+}