ddev: Non-ddev.site hostnames can't work on WSL2, and neither can ddev.site if DNS rebinding disallowed

Describe the bug

When the hostname required for a project is not *.ddev.site, or when DNS rebinding is not allowed, WSL2 browser stuff can’t work.

So:

1. If DNS rebinding is disallowed, ddev will add the hostname to /etc/hosts. But unfortunately it’s the /etc/hosts in the WSL2 system, which is not the hosts file that the browser will use (which is C:\Windows\System32\drivers\etc\hosts). So the browser can’t recognize it.
2. If project_tld is set to something other than ddev.site, same problem
3. If additional_fqdns is set, that has the same problem.

I’m not sure there’s a good solution to this, because WSL2 code can’t change things on the Windows side…

Windows users can work around this issue by manually adding the needed hostnames to C:\Windows\System32\drivers\etc\hosts or by using the windows ddev to issue the command ddev hostname <neededfqdn> 127.0.0.1