MDL-65646 core: Move component storage to json

mod/data/db/subplugins.json

@@ -0,0 +1,6 @@
+{
+    "plugintypes": {
+        "datafield": "mod\/data\/field",
+        "datapreset": "mod\/data\/preset"
+    }
+}

mod/data/db/subplugins.php

@@ -1,4 +1,26 @@
 <?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/>.
 
-$subplugins = array('datafield'  => 'mod/data/field',
-                    'datapreset' => 'mod/data/preset');
+/**
+ * Definition of sub-plugins
+ *
+ * @package   mod_data
+ * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+debugging('Use of subplugins.php has been deprecated. Please provide a subplugins.json instead.', DEBUG_DEVELOPER);
+$subplugins = (array) json_decode(file_get_contents(__DIR__ . "/subplugins.json"))->plugintypes;