Feature: Newsletter

**Is your feature request related to a problem? Please describe.**
We are preparing for launching our own newsletter which means we need to automate some parts of the release of a newsletter.

**Describe the solution you'd like**
When doing a new newsletter we can create a new blog post for it and automatically send the newsletter once published on the website.

**Describe alternatives you've considered**

**Related issues**
- #16
- #19
- #20