nixops: Re-package environment using poetry2nix

The NixOps derivation keeps breaking because of unrelated Python packaging work and is incredibly difficult to keep alive.
Rather than outright removing 1.7 as suggested in NixOS#150059 this change shuold make it much easier to keep 1.7 on life support without causing any burden for those wanting to work on python3 only.

pkgs/tools/package-management/nixops/default.nix

@@ -1,8 +1,15 @@
-{ lib, python2Packages, libxslt, docbook_xsl_ns, openssh, cacert, nixopsAzurePackages ? []
+{ lib, python2, poetry2nix, docbook_xsl_ns, openssh, cacert, nixopsAzurePackages ? []
 , fetchurl, fetchpatch
 }:
 
-python2Packages.buildPythonApplication rec {
+let
+  inherit (poetry2nix.mkPoetryPackages {
+    projectDir = ./python-env;
+    python = python2;
+  }) python;
+  pythonPackages = python.pkgs;
+
+in pythonPackages.buildPythonApplication rec {
   pname = "nixops";
   version = "1.7";
 
@@ -19,23 +26,22 @@ python2Packages.buildPythonApplication rec {
     ./optional-virtd.patch
   ];
 
-  buildInputs = [ libxslt ];
+  buildInputs = [ pythonPackages.libxslt ];
 
-  pythonPath = with python2Packages;
+  pythonPath = (with pythonPackages;
     [ prettytable
       boto
       boto3
       hetzner
-      libcloud
+      apache-libcloud
       adal
       # Go back to sqlite once Python 2.7.13 is released
       pysqlite
       datadog
-      digital-ocean
-      typing
+      python-digitalocean
       ]
       ++ lib.optional (!libvirt.passthru.libvirt.meta.insecure or true) libvirt
-      ++ nixopsAzurePackages;
+      ++ nixopsAzurePackages);
 
   checkPhase =
   # Ensure, that there are no (python) import errors