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.

tests/Import/ImportChainTest.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Tests\Import;
+
+use App\Import\ImportChain;
+use App\Import\ImportInterface;
+use PHPUnit\Framework\TestCase;
+
+class ImportChainTest extends TestCase
+{
+    public function testGetAll()
+    {
+        $import = $this->getMockBuilder(ImportInterface::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $importChain = new ImportChain();
+        $importChain->addImport($import, 'alias');
+
+        $this->assertCount(1, $importChain->getAll());
+        $this->assertSame($import, $importChain->getAll()['alias']);
+    }
+}