Normalise file phpdoc block along the project

[stronk7]

Right now, majority of files have this file phpdoc block:

/*
 * This file is part of the Moodle Plugin CI package.
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * Copyright (c) 2018 Blackboard Inc. (http://www.blackboard.com)
 * License http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

And it has been agreed to change it to:

/*
 * This file is part of the Moodle Plugin CI package.
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @copyright [existing copyright|personal or organization copyright for new files]
 * @license https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

AKA, basically moving the copyright and license to be proper phpdoc tags. Of course, respecting all existing copyrights.