feat: add frontend-plugin-framework slots (#545)

Add the following `frontend-plugin-framework` slots:
* `logo_slot`
* `desktop_main_menu_slot`
* `desktop_secondary_menu_slot`
* `mobile_main_menu_slot`
* `course_info_slot`
* `learning_help_slot`
* `desktop_logged_out_items_slot`
* `mobile_logged_out_items_slot`
* `mobile_user_menu_slot`
* `desktop_user_menu_slot`
* `learning_user_menu_slot`
* `learning_logged_out_items_slot`
* `desktop_header_slot`

src/learning-header/LearningHeaderCourseInfo.jsx

@@ -0,0 +1,23 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+const LearningHeaderCourseInfo = ({
+  courseOrg,
+  courseNumber,
+  courseTitle,
+}) => (
+  <div style={{ minWidth: 0 }}>
+    <span className="d-block small m-0">{courseOrg} {courseNumber}</span>
+    <span className="d-block m-0 font-weight-bold course-title">{courseTitle}</span>
+  </div>
+);
+
+export const courseInfoDataShape = {
+  courseOrg: PropTypes.string,
+  courseNumber: PropTypes.string,
+  courseTitle: PropTypes.string,
+};
+
+LearningHeaderCourseInfo.propTypes = courseInfoDataShape;
+
+export default LearningHeaderCourseInfo;