Find an alternative to Mailgun

[riccardomc]

Mailgun doesn's offer free routes anymore. The next available plan is 35euros/month. We should be able to find a cheaper provider for this. Some alternatives:

• https://www.mailjet.com/pricing/
• https://sendgrid.com/pricing/
• https://www.sparkpost.com/

[riccardomc]

• https://www.zoho.com/mail/zohomail-pricing1.html