stacks: add .env + .env.secrets.ctmpl for identity-and-security stacks

Adds the real Vault Agent secret-rendering templates and non-secret
env vars for authentik, vaultwarden, and wazuh - sanitized (real
domain/email/SMTP provider genericized, kv/<host>/... paths use a
generic 'host' placeholder instead of the real hostname). This is
the standing pattern for the rest of stacks/ going forward.

stacks/identity-and-security/authentik/.env.secrets.ctmpl

@@ -0,0 +1,4 @@
+AUTHENTIK_SECRET_KEY={{ with secret "kv/host/authentik" }}{{ .Data.data.authentik_secret_key }}{{ end }}
+AUTHENTIK_EMAIL__PASSWORD={{ with secret "kv/host/authentik" }}{{ .Data.data.email_password }}{{ end }}
+POSTGRES_PASSWORD={{ with secret "kv/host/authentik" }}{{ .Data.data.pg_pass }}{{ end }}
+AUTHENTIK_POSTGRESQL__PASSWORD={{ with secret "kv/host/authentik" }}{{ .Data.data.pg_pass }}{{ end }}