Add support for generating reports in OpenOffice formats (ODT and ODS)

[damies13]

Is your feature request related to a problem? Please describe.
Add support for generating reports in OpenOffice formats (ODT and ODS), as not everyone has access to MS Office, particularly Linux users, and LibreOffice provides better support for the OpenOffice formats.

Describe alternatives you've considered
You can currently open the docx and xlsx files with LibreOffice, however it's known that the table of contents doesn't work for docx files in LibreOffice.

Additional context
This feature was originally planned for the initial version, but was left out due to time constraints, and not being sure how to implement it.

Two libraries look promising:
odfpy:

• https://pypi.org/project/odfpy/
• https://github.com/eea/odfpy/wiki
• https://github.com/eea/odfpy
• Looks like it's more complete, supports both odt and ods
• has some documentation
• Appears to be a dead project - Improve README.md with project status  eea/odfpy#123

odfdo:

• https://github.com/jdum/odfdo
• Seems to be actively maintained
• not sure if it creates ods files? - maybe needs https://github.com/jdum/odsgenerator for that?
• documentation not as good as odfpy

Need to investigate more....