bulk rename to flupdt, add CLI, add README, add .gitignore

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

flupdt/main.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+from flupdt.flake_show import get_derivations
+from flupdt.cli import parse_inputs
+
+
+def main():
+    args = parse_inputs()
+    print(get_derivations(args.flake_path))
+
+
+if __name__ == "__main__":
+    main()