Port my manual configuration for my router to BSDops

As an "eating my own dogfood" thing, plus motivation to keep working on this.

- [ ] Check whether there already is a debops role for a router, so one that manages things like dhcpd and hostapd.
- [ ] If yes: BSDify it and use it.
- [ ] If not: Make one. Try to get advice from upstream people about what's a DebOps-y way of doing it.

@Evilham hi :D