matrix-synapse: bump to nixos 21.05, new structure

This patches an import path for our new structure, and adjusts the build
inputs for our hacked version of matrix-synapse with a newer version of
twisted (for tls 1.3 support), which is apparently still necessary even
in nixos 21.05.

Seems to build fine (have not waited for all tests in the matrix packag;
these take ages)

pkgs/matrix/default.nix

@@ -15,12 +15,13 @@ self: super:
 
   matrix-synapse = super.matrix-synapse.overrideAttrs (old: {
     propagatedBuildInputs = with self.python3Packages; [
-      setuptools
+      authlib
       bcrypt
       bleach
       canonicaljson
       daemonize
       frozendict
+      ijson
       jinja2
       jsonschema
       lxml
@@ -32,22 +33,20 @@ self: super:
       psutil
       psycopg2
       pyasn1
+      pyjwt
       pymacaroons
       pynacl
       pyopenssl
       pysaml2
       pyyaml
       requests
+      setuptools
       signedjson
       sortedcontainers
       treq
       twisted
-      unpaddedbase64
       typing-extensions
-      authlib
-      pyjwt
-      systemd
-      hiredis
+      unpaddedbase64
     ];
     python = self.python3;
   });

services/matrix-synapse.nix

@@ -3,7 +3,7 @@
 {
   networking.firewall.allowedTCPPorts = [ 80 443 ];
 
-  nixpkgs.overlays = [ (import ./../../../pkgs/matrix) ];
+  nixpkgs.overlays = [ (import ./../pkgs/matrix) ];
 
 
   services.postgresql.enable = true;