- Refactor subimporter New*() funcs to take opt structs.
- Refactor and simplify Vue code.
- Remove redundant i18n entries and use existing ones.
- Remove redundant subimporter constants and use existing ones.
- Consider 'overwrite' option for subscription status as well.
- Write Cypress integration tests for the new feature.
Sending th optional flag as `trunue` in the POST /api/subscrirs
body will skip sending opt-iconfirmation e-mails to subscribers
and mark list subscriptions in the request a`confirmed`.