# What this PR does
This PR moves phone notification logic into separate object PhoneBackend
and introduces PhoneProvider interface to hide actual implementation of
external phone services provider. It should allow add new phone
providers just by implementing one class (See SimplePhoneProvider for
example).
# Why
[Asterisk PR](https://github.com/grafana/oncall/pull/1282) showed that
our phone notification system is not flexible. However this is one of
the most frequent community questions - how to add "X" phone provider.
Also, this refactoring move us one step closer to unifying all
notification backends, since with PhoneBackend all phone notification
logic is collected in one place and independent from concrete
realisation.
# Highligts
1. PhoneBackend object - contains all phone notifications business
logic.
2. PhoneProvider - interface to external phone services provider.
3. TwilioPhoneProvider and SimplePhoneProvider - two examples of
PhoneProvider implementation.
4. PhoneCallRecord and SMSRecord models. I introduced these models to
keep phone notification limits logic decoupled from external providers.
Existing TwilioPhoneCall and TwilioSMS objects will be migrated to the
new table to not to reset limits counter. To be able to receive status
callbacks and gather from Twilio TwilioPhoneCall and TwilioSMS still
exists, but they are linked to PhoneCallRecord and SMSRecord via fk, to
not to leat twilio logic into core code.
---------
Co-authored-by: Yulia Shanyrova <yulia.shanyrova@grafana.com>
* remove email verification related code
* remove email verification related code
* remove sendgrid callback
* remove sendgrid related code
* remove sendgrid related code
* rename sendgrid app to email
* remove email from built-in channels
* remove email from built-in channels
* remove email from built-in channels
* add email backend: https://github.com/grafana/oncall/pull/50
* add email templater
* add email templater
* convert md to html
* add email settings to live settings
* use task to send email, handle some exceptions to create logs
* remove ERROR_NOTIFICATION_MAIL_DELIVERY_FAILED usage
* add email limit logic
* fix tests
* add docs
* remove old email templates
* remove old email templates
* add template_fields to messaging backend
* add messaging backends templates to public api
* add comment for deprecated fields
* fix test
* fix tests
* disable email by default
* don't retry on SMTPException and TimeoutError
* add tests
* bring email back to public api docs
* return ERROR_NOTIFICATION_MAIL_LIMIT_EXCEEDED
* make template_fields tuple
* build_subject_and_title -> build_subject_and_message
* add one more comment about template deprecation
* use 8 as backend id
* add comment about gaierror and BadHeaderError
* add comment on importing in notify_user_async
* edit oss docs
* Remove auto-recreating logic for UserNotificationPolicy
It's removed to get rid of select_for_update on User on each notify_user_task
* Fix and add tests
* remove get_user_policies method
