Remove scenes (#36)

* Remove scenes from the main menu

* Remove scenes from the profile view

* Remove 'scenes explainer' from onboarding flow

* Remove scene-related modals

* Remove member/membership code

* Remove all scenes-related items from notifications

* Remove scene-related code from posts feed

* Remove scene-related API helpers

* Update tests

src/view/screens/Notifications.tsx

@@ -15,7 +15,6 @@ export const Notifications = ({navIdx, visible}: ScreenParams) => {
       return
     }
     store.log.debug('Updating notifications feed')
-    store.me.refreshMemberships() // needed for the invite notifications
     store.me.notifications
       .update()
       .catch(e => {