MBS-13719: Integrate new mail service into MusicBrainz Server

[JadedBlueEyes]

Problem

MBS-13719: Integrate the new email service from my Google Summer of Code project with the MusicBrainz Server to send emails with the latest design!

Solution

• I'm using the LWP instance from $self->c->lwp
• Each request is built manually
• I've added a new configuration option DBDefs->MAIL_SERVICE_BASE_URL
• Request URLs are built off of that
• JSON is serialised with JSON::XS qw( encode_json )

Testing

For each of the ones that I've added so far, I've tested the happy path manually

• creating an account
• reset a password
• Send a message to a user with /user/<id>/contact, with different options set (particularly "Send a copy to my own email address")

Documenting

Draft progress

Language preferences

• Allow users to specify a preferred language for mail
• Send the user's preferred language to the email service

Emails integrated:

• Email verification
• Password reset
• Editor messages
  • Send to self
• Email in use
• Lost username (email lookup)
• Edit note
• edit "No" vote
• Subscriptions

Error handling

• Die when failing to send an email

Tests

• Remove old tests
• Write automated tests for the integration

Further action

Once this is merged, the service will need to be configured and run in production. Updates to musicbrainz-docker might be needed.

[reosarevok]

If this is already a string, why stringify it again?

FWIW, at least locally the string does not seem to be empty.

[JadedBlueEyes]

That issue seems to have resolved itself. I believe it was because it was because bitmap and I were testing with an older version of the Mail service image 🤷. The reason for the two methods of stringification was effectively me throwing stuff at the wall to see what stuck - I can probably remove the first one now.