rbw: add module (#1998)

`rbw` is a stand-alone Bitwarden client, which makes use of a daemon to
cache your password and manage state.

Its configuration can be managed by `home-manager` or not, leaving the
user free to configure it through `rbw config`.

modules/misc/news.nix

@@ -2047,6 +2047,13 @@ in
           configuration file.
         '';
       }
+
+      {
+        time = "2021-05-10T20:41:44+00:00";
+        message = ''
+          A new module is available: 'programs.rbw'.
+        '';
+      }
     ];
   };
 }