This PR adds proper notification on call notifications coming from
single number. To that end following changes have been introduced:
* extension of Notification DB record with contact_id filed
* use of `ContactRecordInterface` in `NotificationsRecordInterface`
* extension of `Increment` query to require `PhoneNumber::View`
* multiple minor changes on path from creating/handling
`NotificationsRecord` to displaying respective notification.
Introduce a new way to handle query responses allowing to deal with
races:
- bind reponse with request,
- handle responses with an observer-like interface.
Signed-off-by: Marcin Smoczyński <smoczynski.marcin@gmail.com>
