TineMCE refactoring

Unified all tinyMCE instances used across AAC, now they are initiated in one single file
+ added option to upload images within editor (CTRL-C CTRL-V)
+ there is new folder: user/, which will be used for all user generated data, like image uploads, guild images, etc.

admin/tools/upload_image.php

@@ -0,0 +1,53 @@
+<?php
+define('MYAAC_ADMIN', true);
+
+require '../../common.php';
+require SYSTEM . 'functions.php';
+require SYSTEM . 'init.php';
+require SYSTEM . 'login.php';
+
+if(!admin())
+	die('Access denied.');
+
+// Don't attempt to process the upload on an OPTIONS request
+if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {
+	header('Access-Control-Allow-Methods: POST, OPTIONS');
+	return;
+}
+
+$imageFolder = USER . 'image_uploads/';
+
+reset ($_FILES);
+$temp = current($_FILES);
+if (is_uploaded_file($temp['tmp_name'])) {
+	header('Access-Control-Allow-Credentials: true');
+	header('P3P: CP="There is no P3P policy."');
+
+	// Sanitize input
+	if (preg_match("/([^\w\s\d\-_~,;:\[\]\(\).])|([\.]{2,})/", $temp['name'])) {
+		header('HTTP/1.1 400 Invalid file name.');
+		return;
+	}
+
+	// Verify extension
+	$ext = strtolower(pathinfo($temp['name'], PATHINFO_EXTENSION));
+	if (!in_array($ext, ['gif', 'jpg', 'png'])) {
+		header('HTTP/1.1 400 Invalid extension.');
+		return;
+	}
+
+	do {
+		$randomName = generateRandomString(8). ".$ext";
+		$fileToWrite = $imageFolder . $randomName;
+	} while (file_exists($fileToWrite));
+
+	move_uploaded_file($temp['tmp_name'], $fileToWrite);
+
+	$returnPathToImage = BASE_URL . 'user/image_uploads/' . $randomName;
+	echo json_encode(['location' => $returnPathToImage]);
+} else {
+	// Notify editor that the upload failed
+	header('HTTP/1.1 500 Server Error');
+}
+
+