flake.nix: Exclude build support from flake exported packages and make pkgs/pkgs.nix obsolete again

flake/inputs-overlay.nix

@@ -0,0 +1,35 @@
+{ self
+, nixpkgs-0dc1c7
+, berlinerbaeder-exporter
+, bij
+, chaosevents
+, harmonia
+, hydra
+, nurausstieg
+, rainbowrss
+, scan-to-gpg
+, ssh-to-age
+, ...
+}@inputs:
+final: prev: {
+  inherit (nixpkgs-0dc1c7.legacyPackages.${final.system})
+    etesync-dav;
+  inherit (berlinerbaeder-exporter.packages.${final.system})
+    berlinerbaeder-exporter;
+  inherit (bij.packages.${final.system})
+    bij;
+  inherit (chaosevents.packages.${final.system})
+    chaosevents;
+  inherit (harmonia.packages.${final.system})
+    harmonia;
+  inherit (hydra.packages.${final.system})
+    hydra;
+  inherit (nurausstieg.packages.${final.system})
+    nurausstieg;
+  inherit (rainbowrss.packages.${final.system})
+    rainbowrss;
+  inherit (scan-to-gpg.packages.${final.system})
+    scan-to-gpg;
+  inherit (ssh-to-age.packages.${final.system})
+    ssh-to-age;
+}