Send notification about opt-in migration
We should add to base-files notification that there is available migration from Turris OS 3.x to Turris OS 5.x and if users are interested that they need to login to Foris, check the migration, and save changes. And if possible that they should do/have a backup in any case.
This notification in my opinion can be done for all routers and later we can do automatic migration on waves, but if you want to do notification on batches as well. I am all in!