Add linter and fixes

.gitignore

@@ -5,3 +5,5 @@ docker/nextcloud/certificates/*
 docker/owncloud/certificates/*
 *.gz
 *.db*
+*.cache
+vendor

.php-cs-fixer.dist.php

@@ -0,0 +1,25 @@
+<?php
+
+$finder = PhpCsFixer\Finder::create()
+    ->in(__DIR__)
+    ->exclude('var')
+;
+
+$config = new PhpCsFixer\Config();
+$config->setRules([
+    '@Symfony' => true,
+    '@PHP70Migration' => true,
+    '@PHP71Migration' => true,
+    '@PHP73Migration' => true,
+    '@DoctrineAnnotation' => true,
+    'doctrine_annotation_array_assignment' => ['operator' => '='],
+    'yoda_style' => false,
+    'strict_comparison' => true,
+    'strict_param' => true,
+    'declare_strict_types' => true,
+    'method_argument_space' => ['on_multiline' => 'ignore'],
+])
+    ->setRiskyAllowed(true)
+    ->setFinder($finder);
+
+return $config;

.php_cs.dist

@@ -0,0 +1,22 @@
+<?php
+
+$finder = PhpCsFixer\Finder::create()
+    ->in(__DIR__)
+    ->exclude('var')
+;
+
+return PhpCsFixer\Config::create()
+    ->setRules([
+        '@Symfony' => true,
+        '@PHP70Migration' => true,
+        '@PHP71Migration' => true,
+        '@PHP73Migration' => true,
+        'array_syntax' => ['syntax' => 'short'],
+        'yoda_style' => false,
+        'strict_comparison' => true,
+        'strict_param' => true,
+        'declare_strict_types' => true,
+    ])
+    ->setRiskyAllowed(true)
+    ->setFinder($finder)
+;