When reuploading full text, check for renamed files

[Daniel-Mietchen]

Some of the files we upload to Commons will be renamed (example: https://commons.wikimedia.org/w/index.php?title=File%3ATrichostetha_bicolor_feeding_on_flowers_of_Agathosma_capensis_%28Rutaceae%29_at_Saldanha_Bay.jpg&diff=133547664&oldid=133547464 ).

When we re-upload a full text to Wikisource (which we should only do in Wikisource namespace), we should check for such renames and use the new ones when embedding the figures.

[notconfusing]

see line 95 in this commit https://github.com/wpoa/recitation-bot/commit/e7b7a3fa9826ba9779c6ee00b1c640713712cdd7