Allow user to set document properties programmatically

[matt-dray]

Is there a programmatic way to adjust document 'properties', i.e. the meta information associated with a spreadsheet file that lists the title, subject, author, category, etc?

This can be found and adjusted manually via File > Properties in spreadsheet programs.

[matt-dray]

To note: this is something that the gptables team would also like to solve, but is also proving difficult in Python given the limits of the xlsx-related packages being wrapped.

[matt-dray]

{dftutils} has a clean_metadata() function that could be useful here; thanks @DIPAD-Fran-Bryden for making me aware of this package.

[matt-dray]

You can set_properties as a method in {openxlsx2}, useful for #70.