Upload email templates

[Nautman]

Since we strive to be fully open source we should also upload the email templates that we use.

[Nautman]

Perhaps we can use the SendGrid API to retrieve single email templates? Either we make a proxy for getting that data from SendGrid servers, or we manually update the emails.

Making a proxy might open up for security issues, but would be cool to do. We would have to limit the actual emails that users should be able to retrieve from SendGrid, and we might have to rate limit.

For a start I think we should simply upload the email templates as JSON.