Add Mailfence to the list of suggested products

[resto1231]

Hello WIll,

Your colleague Radu contacted us (Mailfence) via Twitter for your extension. It's a really cool extension to have as a little companion i was wondering whether you would be willing to add Mailfence?

Thanks a lot

Orestis with Mailfence.

[wgx]

Hey Orestis - please open a pull request on the CSV to add your product in.

[resto1231]

Done.