improved invoices with new renderer (#306)

* added docx renderer and demo template
* added csv renderer and demo template
* added xlsx renderer and demo template
* added ods renderer and demo template
* added user calculator
* added invoice documentation

src/Invoice/Renderer/AbstractRenderer.php

@@ -0,0 +1,82 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Invoice\Renderer;
+
+use App\Twig\DateExtensions;
+use App\Twig\Extensions;
+use Symfony\Component\Translation\TranslatorInterface;
+
+abstract class AbstractRenderer
+{
+    use RendererTrait;
+
+    /**
+     * @var DateExtensions
+     */
+    protected $dateExtension;
+
+    /**
+     * @var Extensions
+     */
+    protected $extension;
+
+    /**
+     * @var TranslatorInterface
+     */
+    protected $translator;
+
+    /**
+     * @param TranslatorInterface $translator
+     * @param DateExtensions $dateExtension
+     * @param Extensions $extensions
+     */
+    public function __construct(TranslatorInterface $translator, DateExtensions $dateExtension, Extensions $extensions)
+    {
+        $this->translator = $translator;
+        $this->dateExtension = $dateExtension;
+        $this->extension = $extensions;
+    }
+
+    /**
+     * @param \DateTime $date
+     * @return mixed
+     */
+    protected function getFormattedDateTime(\DateTime $date)
+    {
+        return $this->dateExtension->dateShort($date);
+    }
+
+    /**
+     * @param $amount
+     * @return mixed
+     */
+    protected function getFormattedMoney($amount)
+    {
+        return $this->extension->money($amount);
+    }
+
+    /**
+     * @param \DateTime $date
+     * @return mixed
+     */
+    protected function getFormattedMonthName(\DateTime $date)
+    {
+        return $this->translator->trans($this->dateExtension->monthName($date));
+    }
+
+    /**
+     * @param $seconds
+     * @return mixed
+     */
+    protected function getFormattedDuration($seconds)
+    {
+        return $this->extension->duration($seconds);
+    }
+}