Co-host websites

During this week's weekly call, we went over the co-hosting feature of IPFS Desktop. I decided to remove it for now and move that code to another branch so we can test it better.

So, we should introduce a section in Settings to add and remove websites from the co-hosting list. It can even be coordinated with IPFS Companion! What if:

1. On Web UI we can manage the websites that get co-hosted.
2. On Companion we can add and remove websites through the toggler.
3. The websites list gets stored to the MFS root file `/.cohosting` or something like that.

**Or...** another idea could be:

Instead of pinning, `.cohosting` could be a directory inside MFS where we would copy the latest hash of some website to.

Both Desktop and Companion could run scripts from time to time to check if the websites were up to date.

@lidel I'd love to hear your opinions on this. It'd be really cool if this got coordinated with IPFS Companion so we'd use the same structure for saving the co-hosting list.

Notice that this would be a list **per repository** and not per installation. That's the only way I can think about now to create this sync'ed feature between Desktop & Companion!