Data/Page Export Options

[chrismclarke]

It had been suggested that we might want to start thinking about options for people to export data from various pages/endpoints, such as pdfs
(see #374 )

One way to do this suggested was to use: https://github.com/Volst/url-to-pdf-api, which uses puppeteer to genenerate pdfs for page urls. Any more discussion on either general or specifics welcome in this thread.

[chrismclarke]

merge into #546