[Rspamd] Various fixes for Rspamd 2.0, neural network activated, autolearning activated (auto-keeps a ratio)

data/conf/rspamd/local.d/statistic.conf

@@ -2,18 +2,23 @@ classifier "bayes" {
     tokenizer {
       name = "osb";
     }
-    autolearn = false;
     backend = "redis";
     min_tokens = 11;
     min_learns = 5;
     new_schema = true;
     expire = 2592000;
     statfile {
-        symbol = "BAYES_HAM";
-        spam = false;
+      symbol = "BAYES_HAM";
+      spam = false;
     }
     statfile {
-        symbol = "BAYES_SPAM";
-        spam = true;
+      symbol = "BAYES_SPAM";
+      spam = true;
+    }
+    autolearn {
+      spam_threshold = 12.0;
+      ham_threshold = -4.5;
+      check_balance = true;
+      min_balance = 0.9;
     }
 }