Allow Instructor To Rename Cohorts And Set Cohort Assignment Method

common/test/acceptance/pages/lms/instructor_dashboard.py

common/test/acceptance/tests/discussion/helpers.py

...est/acceptance/tests/discussion/test_cohort_management.py

lms/static/js/groups/views/cohort_editor.js

lms/static/js/groups/views/cohort_form.js

lms/static/js/spec/groups/views/cohorts_spec.js

lms/static/sass/course/instructor/_instructor_2.scss

...nstructor/instructor_dashboard_2/cohort-editor.underscore

.../instructor/instructor_dashboard_2/cohort-form.underscore

...tor/instructor_dashboard_2/cohort-group-header.underscore

...ructor/instructor_dashboard_2/instructor_dashboard_2.html

openedx/core/djangoapps/course_groups/cohorts.py

...0003_auto__add_coursecohort__add_coursecohortssettings.py

openedx/core/djangoapps/course_groups/models.py

openedx/core/djangoapps/course_groups/tests/helpers.py

openedx/core/djangoapps/course_groups/tests/test_cohorts.py

...e/djangoapps/course_groups/tests/test_partition_scheme.py

openedx/core/djangoapps/course_groups/tests/test_views.py

openedx/core/djangoapps/course_groups/views.py