Use Redis for DKIM keys, define any selector, auto-merge old keys to Redis and fallback to files

data/conf/rspamd/local.d/dkim_signing.conf

@@ -23,6 +23,8 @@ use_domain = "envelope";
 # Whether to normalise domains to eSLD
 use_esld = false;
 # Whether to get keys from Redis
-use_redis = false;
+use_redis = true;
 # Hash for DKIM keys in Redis
-hash_key = "DKIM_KEYS";
+key_prefix = "DKIM_PRIV_KEYS";
+# Selector map
+selector_map = "redis://DKIM_SELECTORS";