MDL-65646 core: Move component storage to json

lib/editor/tinymce/db/subplugins.json

@@ -0,0 +1,5 @@
+{
+    "plugintypes": {
+        "tinymce": "lib\/editor\/tinymce\/plugins"
+    }
+}

lib/editor/tinymce/db/subplugins.php

@@ -24,4 +24,5 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$subplugins = array('tinymce' => 'lib/editor/tinymce/plugins');
+debugging('Use of subplugins.php has been deprecated. Please provide a subplugins.json instead.', DEBUG_DEVELOPER);
+$subplugins = (array) json_decode(file_get_contents(__DIR__ . "/subplugins.json"))->plugintypes;