Enable privacy and handling to be reviewed and modified (#910)

frontend/src/App.jsx

frontend/src/components/SettingsSidebar/index.jsx

frontend/src/pages/GeneralSettings/PrivacyAndData/index.jsx

...end/src/pages/OnboardingFlow/Steps/DataHandling/index.jsx

frontend/src/utils/paths.js

server/models/systemSettings.js

server/utils/helpers/updateENV.js