refactor: rework plugin for new backend and relabel to DTT

BREAKING CHANGE: can't process old JSON format anymore

version.php

-<?php
-// This file is part of Moodle - http://moodle.org/
-//
-// Moodle is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Moodle is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
-
-/**
- * This file contains the version information for the onlinetext modocot plugin
- *
- * @package    assignsubmission_modocot
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-defined('MOODLE_INTERNAL') || die();
-
-$plugin->version   = 2020061500;
-$plugin->requires  = 2019111800; // Moodle 3.8.
-$plugin->component = 'assignsubmission_modocot';
-$plugin->maturity  = MATURITY_STABLE;
-$plugin->release   = "1.0";