Add new course dates fragment.

Also add it to the course home page.

openedx/features/course_experience/views/course_dates.py

@@ -0,0 +1,27 @@
+"""
+Fragment for rendering the course dates sidebar.
+"""
+from django.template.loader import render_to_string
+from opaque_keys.edx.keys import CourseKey
+from web_fragments.fragment import Fragment
+from openedx.core.djangoapps.plugin_api.views import EdxFragmentView
+from courseware.courses import get_course_with_access, get_course_date_blocks
+
+
+class CourseDatesFragmentView(EdxFragmentView):
+    """
+    A fragment to important dates within a course.
+    """
+    def render_to_fragment(self, request, course_id=None, **kwargs):
+        """
+        Render the course dates fragment.
+        """
+        course_key = CourseKey.from_string(course_id)
+        course = get_course_with_access(request.user, 'load', course_key, check_if_enrolled=False)
+        course_date_blocks = get_course_date_blocks(course, request.user)
+
+        context = {
+            'course_date_blocks': course_date_blocks
+        }
+        html = render_to_string('course_experience/course-dates-fragment.html', context)
+        return Fragment(html)