Use PHPMailer for sending mails

Closes: #1

phpcs-errors:226 phpunit-status:successful phpstan-errors:207

.gitignore

@@ -1,6 +1,7 @@
-/csv
 /cache
 /composer.lock
+/csv
+/conf/MD_CONF_EMAIL.php
 /translation-importer
 /values/langfiles
 *.swp

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "classes/MDTlLoader"]
 	path = classes/MDTlLoader
 	url = /var/www/vhosts/museum-digital.de/git-base/MDTlLoader/
+[submodule "classes/MDMailer"]
+	path = classes/MDMailer
+	url = /var/www/vhosts/museum-digital.de/git-base/MDMailer

composer.json

@@ -1,5 +1,8 @@
 {
     "require-dev": {
         "phpunit/phpunit": "^8.4"
+    },
+    "require": {
+        "phpmailer/phpmailer": "^6.1"
     }
 }

functions/functions.php

@@ -9,10 +9,14 @@
 declare(strict_types = 1);
 
 // Set autoloader
+error_reporting(E_ALL);
+ini_set('display_errors', "1");
 spl_autoload_register("mdCsvxmlAutoloader");
 set_exception_handler("mdExceptionHandler");
 set_error_handler("mdErrorHandler", E_ALL);
 
+require_once __DIR__ . '/../vendor/autoload.php';
+
 /**
  * Autoloader for museum-digital.org.
  *
@@ -28,6 +32,8 @@ function mdCsvxmlAutoloader(string $className):void {
         __DIR__ . "/../classes/MDAllowedValueSets/src",
         __DIR__ . "/../classes/MDExportFormats/src",
         __DIR__ . "/../classes/MDErrorReporter",
+        __DIR__ . "/../classes/MDMailer/src",
+        __DIR__ . "/../conf",
         __DIR__ . "/../classes/MDErrorReporter/exceptions/generic",
         __DIR__ . "/../classes/MDErrorReporter/exceptions/page",
         __DIR__ . "/../classes/MDErrorReporter/exceptions/updates",

index.php

@@ -34,7 +34,6 @@ $toInject = '
 ';
 echo printHTMLHead($toInject);
 
-
 echo '
 
 <div class="uploader">