pythonPackages.diagrams: init at 0.19.1

Add python diagrams library. Generate nice architecture diagrams
with python code, allowing for rapid iteration.

The images are rendered using dot from graphviz.

This PR is based on the upstream GitHub repo for diagrams, which
differs significantly from the tarball published to pypi.

Closes #101532

pkgs/development/python-modules/diagrams/build_poetry.patch

@@ -0,0 +1,12 @@
+diff --git a/pyproject.toml b/pyproject.toml
+index 2c93a39..6c800e2 100644
+--- a/pyproject.toml
++++ b/pyproject.toml
+@@ -24,3 +24,7 @@ isort = "^4.3"
+ 
+ [tool.black]
+ line-length = 120
++
++[build-system]
++requires = ["poetry_core>=1.0.0"]
++build-backend = "poetry.core.masonry.api"

pkgs/development/python-modules/diagrams/default.nix

@@ -0,0 +1,49 @@
+{ lib
+, buildPythonPackage
+, pythonOlder
+, fetchFromGitHub
+, black
+, jinja2
+, poetry-core
+, round
+, graphviz
+, inkscape
+, imagemagick
+, pytestCheckHook
+}:
+
+buildPythonPackage rec {
+  pname = "diagrams";
+  version = "0.19.1";
+  format = "pyproject";
+  disabled = pythonOlder "3.6";
+
+  src = fetchFromGitHub {
+    owner = "mingrammer";
+    repo = pname;
+    rev = "v${version}";
+    sha256 = "0qvk0cp3026n5jmwp9z7m70b6pws0h6a7slxr23glg18baxr44d4";
+  };
+
+  preConfigure = ''
+    patchShebangs autogen.sh
+    ./autogen.sh
+  '';
+
+  patches = [ ./build_poetry.patch ];
+
+  checkInputs = [ pytestCheckHook ];
+
+  # Despite living in 'tool.poetry.dependencies',
+  # these are only used at build time to process the image resource files
+  nativeBuildInputs = [ black inkscape imagemagick jinja2 poetry-core round ];
+
+  propagatedBuildInputs = [ graphviz ];
+
+  meta = with lib; {
+    description = "Diagram as Code";
+    homepage    = "https://diagrams.mingrammer.com/";
+    license     = licenses.mit;
+    maintainers =  with maintainers; [ addict3d ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -1553,6 +1553,8 @@ in {
 
   dftfit = callPackage ../development/python-modules/dftfit { };
 
+  diagrams = callPackage ../development/python-modules/diagrams { };
+
   diceware = callPackage ../development/python-modules/diceware { };
 
   dicom2nifti = callPackage ../development/python-modules/dicom2nifti { };