no issue
- adds new router to the frontend for handling unsubscribe
- default template lives in `core/server/frontend/views/unsubscribe.hbs`
- `{{error}}` is present and contains the error message when unsubscribe fails
- `{{member}}` is present and contains the member email
- updated unsubscribe url to match the new format
refs #10790
refs #9528
- The settings service was designed to handle more settings then just routing, but till this day there wasn't anything else added. As routes.yaml is only being used by frontend router so conceptually it fits better to have this code in frontend, so that it doesn't have to reach out to server
- The code left in server settings is the one that interacts with the database `settings` table and only partially provides information to frontend. That part is known as 'settings cache' and will be accessed through API controllers.
refs #10790
- Moved /core/apps into core/frontend
- Moved /core/server/helpers to /core/frontend/helpers along with /core/server/services/themes
- Changed helper location in overrides
- Moved /core/server/services/routing to /core/frontend/services
- Moved /core/server/services/url to /core/frontend/services
- Moved /core/server/data/meta to /core/frontend/meta
- Moved /core/server/services/rss to /core/frontend/services
- Moved /core/server/data/xml to /core/frontend/services
