MDL-40126 Enrolments: Implemented two webservices to get enrolment instance info

1. core_enrol_get_course_enrolment_methods() which returns all enrolment method instances
which implement get_enrol_info()
2. enrol_self_get_instance_info() will return information about self enrolment instance.

enrol/self/db/services.php

@@ -0,0 +1,34 @@
+<?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/>.
+
+/**
+ * Self enrol plugin external functions and service definitions.
+ *
+ * @package   enrol_self
+ * @copyright 2013 Rajesh Taneja <rajesh@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since     Moodle 2.6
+ */
+
+$functions = array(
+    'enrol_self_get_instance_info' => array(
+        'classname'   => 'enrol_self_external',
+        'methodname'  => 'get_instance_info',
+        'classpath'   => 'enrol/self/externallib.php',
+        'description' => 'self enrolment instance information.',
+        'type'        => 'read'
+    )
+);