type safe subscriptions module

...nd/src/components/feedback_list/FeedbackSearchOptions.vue

frontend/src/components/feedback_list/FeedbackTable.vue

...ssion_notes/toolbars/AnnotatedSubmissionBottomToolbar.vue

...end/src/components/subscriptions/SubscriptionCreation.vue

...tend/src/components/subscriptions/SubscriptionForList.vue

frontend/src/components/subscriptions/SubscriptionList.vue

...nd/src/components/subscriptions/SubscriptionsForStage.vue

frontend/src/components/tutor_list/TutorList.vue

frontend/src/models.ts

frontend/src/pages/SubscriptionWorkPage.vue

frontend/src/pages/base/FeedbackHistoryPage.vue

frontend/src/pages/reviewer/TutorOverviewPage.vue

frontend/src/store/actions.ts

...rc/store/modules/feedback_list/feedback-search-options.ts

frontend/src/store/modules/feedback_list/feedback-table.ts

frontend/src/store/modules/subscriptions.ts

frontend/src/store/store.ts