New program: Export books of *other* members as CSV

[andre-st]

Export books of other members as CSV-file so you can use their data with any stats-generating software on GitHub or the Web which expects you to upload "your" CSV-export file.

The background of this feature request is this and the following posts:
https://www.goodreads.com/topic/show/19691062-select-lists-being-retired?page=4&ref=nav_bar_discussions_pane_discussion#comment_188846552

[andre-st]

If there's real interest, I'll continue this. At the moment, I neither see myself nor do I see anyone else using it. So I stopped working on this feature.