Change name of settings; add migration

packages/rocketchat-custom-sounds/client/lib/CustomSounds.js

packages/rocketchat-i18n/i18n/en.i18n.json

packages/rocketchat-lib/server/models/Subscriptions.coffee

...-notifications/client/views/pushNotificationsFlexTab.html

...sh-notifications/client/views/pushNotificationsFlexTab.js

...-notifications/server/methods/saveNotificationSettings.js

...ketchat-push-notifications/server/models/Subscriptions.js

...s/rocketchat-ui-account/account/accountPreferences.coffee

...ges/rocketchat-ui-account/account/accountPreferences.html

packages/rocketchat-ui/lib/notification.coffee

server/methods/saveUserPreferences.coffee

server/publications/subscription.coffee

server/startup/migrations/v077.js