Product Releases: Custom Domains

First release: users connect their own domains to a server's address on a "Domains" page, with the DNS records to create and a DNS check (A/AAAA or CNAME, optional TXT record). Caddy on one or more proxy hosts serves them with automatic HTTPS; a small agent fetches the Caddyfile from the panel every minute, validates it, reloads Caddy and reports back. Admin page with proxy hosts, install commands, settings (eggs, domains per server, TXT verification, certificate e-mail) and all domains. Hourly cleanup of domains of deleted servers and addresses.
Update notice: when a newer version is out, Admin > Extensions and the licence box on the admin page show it, with what is new. With the optional update helper (set up once as root), the update runs with one click after a backup of the panel files and the database.