heise Developer: pitch a specialist article

### Problem

heise Developer runs a documented programme for outside technical articles. It is the best-fitting outlet for Fallout: a paid specialist article rather than a product announcement.

### Outcome

A topic proposal is sent, and either a commissioned article or a clear no.

### Terms, from the author guidelines

- Contact: `nikr@ix.de`, subject `Autorenvereinbarung für heise Developer`.
- They prefer agreeing the topic first over receiving an unsolicited manuscript.
- Roughly 6500 characters is the billing unit. Fee is about 140 EUR per 6500 characters, paid on publication.
- Markdown in UTF-8 preferred. Third person only, no "wir" or "ich", or the desk rewrites it.
- Exclusive contributions only.
- Needs an author agreement before publication, plus a two to three sentence bio, a photo, and bank details.

### Acceptance criteria

- [ ] Topic proposal sent to `nikr@ix.de`.
- [ ] Reply recorded here.

### Notes

Guidelines: https://www.heise.de/developer/Hinweise-fuer-Autoren-und-Autorinnen-1218380.html

Part of #605.