ostree: enable ed25519 support

This was omitted in the latest update.

Only adds ~400 KB.

It required adding openssl to tests so I tacked on some cleanups.
In particular, the GI_TYPELIB_PATH was already being set in the wrapper
so we can remove it from the module (not sure why Gtk was even there).

Also switched away from using pkgconfig and docbook_xsl aliases
and reordered the expression a bit.

nixos/tests/installed-tests/ostree.nix

@@ -3,21 +3,10 @@
 makeInstalledTest {
   tested = pkgs.ostree;
 
-  # TODO: Wrap/patch the tests directly in the package
   testConfig = {
     environment.systemPackages = with pkgs; [
-      (python3.withPackages (p: with p; [ pyyaml ]))
       gnupg
       ostree
     ];
-
-    # for GJS tests
-    environment.variables.GI_TYPELIB_PATH = lib.makeSearchPath "lib/girepository-1.0" (with pkgs; [
-      gtk3
-      pango.out
-      ostree
-      gdk-pixbuf
-      atk
-    ]);
   };
 }