Implement multilanguage

This completes the multilanguage support

For this a new setting in the config got added "defaultLanguage"

lang/mail.en-gb.php

@@ -0,0 +1,118 @@
+<?php
+/**
+ * Copyright 2018 Matthias Kesler
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+function send_mail($receiver, $subject, $body) {
+	include("config.php");
+	$headers = "From: " . $config["register_email"] . "\r\n"
+		. "Content-Type: text/plain;charset=utf-8";
+	return mail($receiver, $subject, $body, $headers);
+}
+
+function send_mail_pending_verification($homeserver, $user, $receiver, $verify_url) {
+	$subject = "Pleast approve your registration request on $homeserver";
+	$body = "Dear " . $user . ",
+
+It seems that you tried to register on $homeserver.
+This homeserver requires a two step registration.
+
+For this we want you to verify that you want to register. For this please click on this link:
+$verify_url
+
+The admins will informed about your registration request once you clicked on this link.
+
+Note: This registration request will be cleaned up in 48 hours.
+Others might take your username afterwards.
+
+Thanks for your patience.
+
+The admin team of " . $homeserver;
+	return send_mail($receiver, $subject, $body );
+}
+
+function send_mail_pending_approval($homeserver, $user, $receiver) {
+	$subject = "Registration is pending verification from an admin";
+	$body = "Dear " . $user . ",
+
+You have verified your registration request. The admins are now checking your request.
+
+You will get an email once they approve or decline your request.
+
+Sincerely,
+
+The admin team of " . $homeserver;
+	return send_mail($receiver, $subject, $body );
+}
+
+function send_mail_registration_allowed_but_failed($homeserver, $user, $receiver) {
+	$subject = "Registration on $homeserver got approved";
+	$body = "Dear " . $user . ",
+
+Your registration request got approved by the admin team.
+
+But there was a problem when triggering the registration request. It will be retried in a few minutes.
+We hope that the issue will be fixed soon.
+You will get another email with initial credentials once the registration got handled completely.
+
+The admin team of " . $homeserver;
+	return send_mail($receiver, $subject, $body);
+
+}
+
+function send_mail_registration_success($homeserver, $user, $receiver, $username, $password, $howToURL) {
+	$subject = "Registration on $homeserver got approved";
+	$body = "Dear " . $user . ",
+
+Your registration request got verified by the admin team.
+
+To log in you can use the following credentials::
+Username: $username
+Password: $password
+
+Important: Please change your password as soon as possible after your first login.
+The password is not stored in clear text on the server but people could get access to this mail
+and compromise your account.
+";
+if (!empty($howToURL)) {
+	$body .= "
+You can find further help here::
+$howToURL\n";
+}
+	$body .= "
+Enjoy your usage of $homeserver.
+You can ask further questions inside of the chat system.
+
+The admin team of " . $homeserver;
+	return send_mail($receiver, $subject, $body);
+
+}
+function send_mail_registration_decline($homeserver, $user, $receiver, $reason) {
+	$subject = "Registration on $homeserver declined.";
+	$body = "Guten Tag " . $user . ",
+
+Your registration request got declined by the admin team.\n";
+
+	if (empty($reason)) {
+		$body .= "\nThey did not provide any reason for this\n";
+	} else {
+		$body .= "\nThey provide following hint for you:\n$reason\n";
+	}
+
+	$body .= "
+We hope that you can understand this reason.
+
+The admin team of " . $homeserver;
+	return send_mail($receiver, $subject, $body );
+}
+?>