refactor of export codebook so that it the exported file is generated after clicking the button (not after every change of codebook, categories and links between them)
some things to consider:
when exporting memo (and codebook), I do not put timestamp into the filename (because it causes error when testing due to different snapshot filenames). I think it is ok, user is warned when the same file exists and export would be overwritten and can change the filename.
Changes:
some things to consider: