refactor: move the public host out to vantage-site and vantage-docs

site/ and sitesvc/ become web/ and server/ in vantage-site; docsite/
becomes the root of vantage-docs. Their images move with them, to
vantage/vantage-site/{web,server} and vantage/vantage-docs.

Nothing here imported any of them, and sitesvc turned out to read no
database at all, so both cuts are clean. docker-compose.site.yml is
deleted rather than emptied: every service it held now ships with the
repository that builds it, and deploy/docker/docker-compose.yml is once
again exactly a self-hosted install.

Corrects four comments that named sitesvc for work it no longer does.

deploy/chart/vantage/templates/ingress.yaml

@@ -15,8 +15,8 @@ The web host is normally a wildcard — `*.vantage.example.com` — because that
 the per-tenant instance namespace; APP_ROOT_LABEL resolves the instance from the
 label. Kubernetes wildcard hosts match exactly one label, so this does not match
 the apex, and on the deployment this chart was written for it must not: the apex
-is the marketing site, a separate application (see site/ and
-docker-compose.site.yml). extraHosts exists for a genuine second name, not for
+is the marketing site, a separate application in the vantage-site repository.
+extraHosts exists for a genuine second name, not for
 reclaiming the apex.
 
 Agents reach the server's gRPC port, which is plain h2c — the server holds no