move python packages to pkgs/python-packages

Remove obsolete passthru from joinmarket because joinmarket packages are
now accessible via pkgs/python-packages.

pkgs/python-packages/jmbase/default.nix

@@ -0,0 +1,16 @@
+{ version, src, lib, buildPythonPackage, fetchurl, future, twisted, service-identity, chromalog }:
+
+buildPythonPackage rec {
+  pname = "joinmarketbase";
+  inherit version src;
+
+  postUnpack = "sourceRoot=$sourceRoot/jmbase";
+
+  propagatedBuildInputs = [ future twisted service-identity chromalog ];
+
+  meta = with lib; {
+    homepage = "https://github.com/Joinmarket-Org/joinmarket-clientserver";
+    maintainers = with maintainers; [ nixbitcoin ];
+    license = licenses.gpl3;
+  };
+}