Multisite on different domains

Grav now supports Multisite at the subdomain or subdirectory level:

**1. Subdomain**

```
https://example.com --> /user/
https://subsite1.example.com --> /user/env/subsite1.example.com
https://subsite2.example.com --> /user/env/subsite2.example.com
```

**2. Subdirectory**

```
https://example.com --> /user/
https://example.com/subsite1 --> /user/env/subsite1
https://example.com/subsite2 --> /user/env/subsite2
```

However, I would welcome the possibility of operating the environment on different domains (languages, countries, products, etc.):

**3. Languages**

```
https://example.com --> /user/
https://example.cz --> /user/env/example.cz
https://example.fr --> /user/env/example.fr
```

**4. Products**

```
https://corporatesite.tld --> /user/
https://product1.tld --> /user/env/product1.tld
https://product2.tld --> /user/env/product2.tld
```

Would it be possible to implement support since Grav v1.8?

No files or tests are mentioned. Start by reviewing Grav's existing multisite handling for subdomains and subdirectories, then trace how the host maps to the environment path. Done should include support for separate domains such as language or product domains, with the expected mappings documented and verified.

Written by the indexing model from the issue text.