Added create feedback e2e tests

Makefile

frontend/src/components/SubmissionTests.vue

frontend/src/components/SubmissionType.vue

.../src/components/submission_notes/SubmissionCorrection.vue

...tend/src/components/submission_notes/base/CommentForm.vue

...ssion_notes/toolbars/AnnotatedSubmissionBottomToolbar.vue

frontend/src/components/subscriptions/SubscriptionEnded.vue

frontend/src/components/subscriptions/SubscriptionList.vue

functional_tests/test_feedback_creation.py

functional_tests/test_front_pages.py

functional_tests/util.py

util/factory_boys.py