factor out components with callPackage to allow for easier overrides

Before this change it was very inconvenient to override specific
dependencies, e.g. patching something in pythonEnv and having its
dependents use that patched version.
This is just a step towards better overridability for the individual
authentik components, because patched versions of components still need
to be manually passed to their dependents. An overlay-like approach
would be even better.

components/docs.nix

@@ -0,0 +1,21 @@
+{ authentik-src
+, authentik-version
+, buildNapalmPackage
+, nodejs_20
+}:
+
+buildNapalmPackage "${authentik-src}/website" {
+  version = authentik-version; # 0.0.0 specified upstream in package.json
+  NODE_ENV = "production";
+  nodejs = nodejs_20;
+  npmCommands = [
+    "cp -v ${authentik-src}/SECURITY.md ../SECURITY.md"
+    "cp -vr ${authentik-src}/blueprints ../blueprints"
+    "npm install --include=dev"
+    "npm run build-docs-only"
+  ];
+  installPhase = ''
+    rm -r ../website/node_modules/.cache
+    mv -v ../website $out
+  '';
+}