A good looking E-Mail template

[Flajt]

Is your feature request related to a problem? Please describe.
I would like to have a decent looking E-Mail template, so that the E-Mails with the verification files don't look like spam.

Describe the solution you'd like
A simple HTML / CSS template which can be used by webhook.go

Describe alternatives you've considered
Let it be

Additional context
I would have to read up if we can pass it via file or otherwise.
It should look pleasing to the eye!