Implement CLI commands for batch extraction and PDF generation

- Added command-line interface using Click for `batch_extractor.py` to handle extraction from ZIP and PDF files.
- Enhanced `save_to_excel` function to create parent directories for output files.
- Updated `build_pdf.py` to include a CLI for generating PDF labels from Excel data.
- Improved README.md with detailed usage instructions for the new CLI commands.
- Added `click` to requirements.txt for command-line functionality.

requirements.txt

@@ -4,4 +4,5 @@ reportlab
 pandas
 treepoem
 openpyxl
-pymupdf
+pymupdf
+click