The hive-domain vhost renders where a hive or the homeserver runs. Its
matrix .well-known JSON and /matrix/ redirect are served wherever the
homeserver runs; the dashboard, swagger UI, agent routes and the
agents.conf include only where a hive runs, since they proxy to hive-c0re.
The gateway doc's vhost map says which rows exist without a hive, and the
trust-bundle text describes ca.pem by what it is rather than as retired.
Refs #4588
3e1ac4e678