feat(kanidm): scale down to single replica, remove replication

Drop from 3 replicas to 1. Remove init container, repl-certs secret,
replication port, podAntiAffinity, server-1/2 configs, and replication
stanza from server-0.toml. Mount configmap directly via subPath.

apps/base/kanidm/resources/server-0.toml

@@ -13,7 +13,3 @@ log_level = "info"
 path = "/data/backups/"
 schedule = "0 22 * * *"
 versions = 7
-
-[replication]
-origin = "repl://kanidm-0.kanidm-headless.kanidm.svc.cluster.local:8444"
-bindaddress = "[::]:8444"