[FEATURE] Subdomain wildcard / regex

### What's needed and why?

Sometimes you want to forward all subdomains to your upstream proxy. If you got multiple TLDs for example, you'd have to declare a config for each of them. Also you might want to capture all subdomains. I added some examples below

### Implementations ideas (optional)

Add the ability to use a regex, here are some examples of how one could use it:

```
.*\.?example\.com - Allow any subdomain like test.example.com 24hours.example.com
[a-z]+\.example\.com - Allow any char subdomains like test.example.com abc.example.com
example\.(com|net|org) - Catch multiple TLDs at once like example.com example.net example.org
```

### Code of Conduct

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