electrs: add netns

- Adds electrs to netns-isolation.services
- Adds daemonrpc option and specifies address option to allow using
  electrs with network namespaces
- Adds host option (defaults to localhost) as target of hidden service

modules/netns-isolation.nix

@@ -100,6 +100,11 @@ in {
           id = 15;
           connections = [ "bitcoind" ];
         };
+        electrs = {
+          id = 16;
+          connections = [ "bitcoind" ]
+          ++ ( optionals config.services.electrs.TLSProxy.enable [ "nginx" ]);
+        };
       };
 
       systemd.services = {
@@ -240,6 +245,13 @@ in {
         '';
       };
 
+      # electrs: Custom netns configs
+      services.electrs = mkIf config.services.electrs.enable {
+        host =  if config.services.electrs.TLSProxy.enable then netns.nginx.address else netns.electrs.address;
+        address = netns.electrs.address;
+        daemonrpc = "${netns.bitcoind.address}:${toString config.services.bitcoind.rpc.port}";
+      };
+
     })
     # Custom netns config option values if netns-isolation not enabled
     (mkIf (!cfg.enable) {