Add great open source email services like Tutanota and ProtonMail

Tutanota Website: https://tutanota.com/ GitHub Link: https://github.com/tutao/tutanota/

ProtonMail Website: https://protonmail.ch/ GitHub Link: https://github.com/ProtonMail/WebClient Blog Post: https://blog.protonmail.ch/protonmail-open-source/

What do you think?