Add HOSTKEY to hosting providers list

[etofarkhad]

{
    "name": "HOSTKEY B.V.",
    "link": "https://hostkey.com",
    "category": "full",
    "tutorial": "",
    "announcement": "https://hostkey.com/apps/developer-tools/free-domain-certbot/",
    "plan": "",
    "reviewed": "2025.12.01",
    "note": "All pre-installed software comes with a free Let’s Encrypt certificate"
}

hosting provider - HOSTKEY B.V.
relevant link - https://hostkey.com/apps/developer-tools/free-domain-certbot/
partner category - Full HTTPS Support
note - All pre-installed software comes with a free Let’s Encrypt certificate

[ohemorange]

Could you please create a pull request with these changes?

[ohemorange]

Please create a PR adding an entry to https://github.com/certbot/website/blob/master/_data/hosting_providers.json