Remove domains that don't need renewing

We no longer need to redirect these domains:
* [guardianhomeinsurance.com](http://guardianhomeinsurance.com/)
* [businessunlimited.co.uk](http://businessunlimited.co.uk/)
* [computingunlimited.co.uk](http://computingunlimited.co.uk/)
* [foodunlimited.co.uk](http://foodunlimited.co.uk/)
* [londonunlimited.co.uk](http://londonunlimited.co.uk/)
* [musicunlimited.co.uk](http://musicunlimited.co.uk/)
* [graduatesunlimited.co.uk](http://graduatesunlimited.co.uk/)

Relevant repos:
* https://github.com/guardian/domains-platform
* https://github.com/guardian/fastly-edge-cache/blob/main/domains/README.md?plain=1

There is probably a bit of clean-up to do.
There is no deadline.