Remove openpyxl from sources

.gitignore

PreCourlis/__init__.py

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/INSTALLER

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/LICENCE.rst

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/METADATA

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/RECORD

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/REQUESTED

PreCourlis/external_lib/openpyxl-3.1.2.dist-info/WHEEL

...urlis/external_lib/openpyxl-3.1.2.dist-info/top_level.txt

PreCourlis/external_lib/openpyxl/__init__.py

PreCourlis/external_lib/openpyxl/_constants.py

PreCourlis/external_lib/openpyxl/cell/__init__.py

PreCourlis/external_lib/openpyxl/cell/_writer.py

PreCourlis/external_lib/openpyxl/cell/cell.py

PreCourlis/external_lib/openpyxl/cell/read_only.py

PreCourlis/external_lib/openpyxl/cell/rich_text.py

PreCourlis/external_lib/openpyxl/cell/text.py

PreCourlis/external_lib/openpyxl/chart/_3d.py

PreCourlis/external_lib/openpyxl/chart/__init__.py

PreCourlis/external_lib/openpyxl/chart/_chart.py