massive rewrite using flake-parts

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

pkgs/customscripts/src/x0

@@ -0,0 +1,6 @@
+#!/usr/bin/env nix-shell
+#! nix-shell -i bash -p curl
+for x in "$@"; do
+  curl -F "file=@\"$x\"" https://x0.at/
+  echo " "
+done