Define subplugins.json (#312)

db/subplugins.json

@@ -0,0 +1,5 @@
+{
+    "plugintypes": {
+        "customcertelement": "mod\/customcert\/element"
+    }
+}

db/subplugins.php

@@ -1,27 +0,0 @@
-<?php
-// This file is part of the customcert module for 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/>.
-
-/**
- * Definition of sub-plugins.
- *
- * @package    mod_customcert
- * @copyright  2013 Mark Nelson <markn@moodle.com>
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-defined('MOODLE_INTERNAL') || die();
-
-$subplugins = array('customcertelement' => 'mod/customcert/element');