keep authelia's oidc client secrets in the store, not on disk

The mint creates each client's secret in the swarm secret store and writes only the digest to disk. It mints only when the store answers and holds none. A new unit moves the plaintext files an earlier release left into the store and removes each once the store holds the same value. The bridge reads its secret from the store into /run before each start. The secret publisher unit and its path unit are gone.

swarm-notify-router/src/main.rs

@@ -381,8 +381,8 @@ async fn client_secret(client_id: &str) -> Result<String> {
     match stored {
         Some(s) if !s.value.trim().is_empty() => Ok(s.value.trim().to_owned()),
         _ => bail!(
-            "nothing at {path}: swarm-secret-publish, in authelia's container, has not \
-             published this service's client secret"
+            "nothing at {path}: authelia's mint, in its container, has not \
+             stored this service's client secret"
         ),
     }
 }