```
*An* `ActiveRecord::StatementInvalid` *occurred while* `POST </settings/import>` *was processed by* `imports#create`
Exception
----------------
PG::NotNullViolation: ERROR:  null value in column "type" violates not-null constraint
```

* Allow export of mutes list

* Allow importing of mutes list

* Refactor to use Settings::Exports::BaseController and DRY up exports code