Update joinmarket.nix

add recommended settings and how to change them

system/bitcoin/joinmarket.nix

@@ -1,11 +1,28 @@
 ### JOINMARKET
-{
+### https://github.com/fort-nix/nix-bitcoin/blob/master/modules/joinmarket.nix
+{lib,...}: {
   services = {
     joinmarket = {
     # Set this to enable the JoinMarket service, including its command-line scripts.
     # These scripts have prefix 'jm-', like 'jm-tumbler'.
     # Note: JoinMarket has full access to bitcoind, including its wallet functionality.
     enable = true;
+    # To see all available settings, check: 
+    # https://raw.githubusercontent.com/JoinMarket-Org/joinmarket-clientserver/master/src/jmclient/configure.py
+    settings = {
+      # Change your preferred taker fees here
+      POLICY = {
+        max_cj_fee_rel = 0.00002;
+        max_cj_fee_abs = 1000;
+      };
+      # Recommended setting adjustment: override default directory nodes. The following
+      # setting makes joinmarket use the updated directory nodes. 
+      # See this issue: https://github.com/JoinMarket-Org/joinmarket-clientserver/issues/1445
+      # You can also check the status of directory nodes here: https://directories.w3ird.tech/
+      "MESSAGING:onion" = {
+        directory_nodes = lib.mkForce "satoshi2vcg5e2ept7tjkzlkpomkobqmgtsjzegg6wipnoajadissead.onion:5222,shssats5ucnwdpbticbb4dymjzf2o27tdecpes35ededagjpdmpxm6yd.onion:5222,coinjointovy3eq5fjygdwpkbcdx63d7vd4g32mw7y553uj3kjjzkiqd.onion:5222,nakamotourflxwjnjpnrk7yc2nhkf6r62ed4gdfxmmn5f4saw5q5qoyd.onion:5222";
+      };
+    };
     # 
     # Set this to enable the JoinMarket Yield Generator Bot. You will be able to
     # earn sats by providing CoinJoin liquidity. This makes it impossible to use other