Switch to PSR-compatible version of shadowhand/email, refs T612

Summary:
- updates to latest email package with PSR support
- remove module reference

Test Plan:
```
composer install
```

Reviewers: eyedol, rjmackay

Reviewed By: rjmackay

Subscribers: srutto, bodacea, dkobia

Maniphest Tasks: T612

Differential Revision: https://phabricator.ushahidi.com/D282