Create the headings page

[kevinb1989]

I have never created any spreadsheet without headings. I have never seen spreadsheets without headings either. Headings are crucial.

And it took me quite a bit of time to figure out how to add headings from the docs. I finally found that section in the Mapping data page.

I want to create a new page just for adding headings for exporting, like we already have a similar page for importing.

[patrickbrouwers]

Can you add it to the navigation too

[kevinb1989]

@patrickbrouwers No problem, I do so now.