Feat: Whatsapp notifications

[jonathansberry]

Description

Implements whatsapp notifications.

Since SMS and Whatsapp notifications share a great deal of logic and the same gateway, I have combined the logic into a single flow called "send_phone_notifications". This avoids having to loop through every user in the site to form a condensed copy of their dashboard activity stream twice. I would have maybe liked to find a better name for the action, but I couldn't come up with anything.

I have also refactored the code to make the send_phone_notifications action more readable without so many nested function calls.

I have also moved email_notifications code over into it's own named module.

Testing

Included tests for the whatsapp notifications and the validation of user extra fields. Also included a test to ensure that whatsapp notifications comply with pre-approved templates.

Documentation

Doc string for the send_twilio_notifications action.

Checklist

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• The Jira ticket for this issue has been updated to "Ready to Review" or equivalent.
• I have developed these changes in discussion with the appropriate project manager.
• My code follows the general Fjelltopp documentation (see Confluence).
• I have made corresponding changes to the Fjelltopp documentation (see Confluence).
• I have rebased this branch with master.
• New dependency changes have been committed.
• I have added automated tests that prove my fix is effective or that my feature works.
• New and existing tests pass locally with my changes.
• My changes generate no new warnings.
• I have performed a self-review of my own code.
• I have assigned at least one reviewer.
• I have assigned at least one label to this PR: "patch", "minor", "major".