chore: add project documentation, restrict email import permissions, and set date format in InboxPage

paperless-frontend/src/pages/InboxPage.tsx

@@ -434,6 +434,7 @@ export default function InboxPage() {
               {field.type === 'date' ? (
                 <DatePicker
                   style={{ width: '100%' }}
+                  format="DD.MM.YYYY"
                   value={fieldValues[field.name] ? dayjs(fieldValues[field.name]) : null}
                   onChange={(d) =>
                     setFieldValues((prev) => ({