Add per connector option to zip data before upload

[juriroemer]

e.g. Zenodo can not reflect directory structures (thanks @borsna)

[borsna]

https://github.com/sandes/zipfly or similar could be used to create a zip stream when sending the files to e.g. zenodo.
I think it would be good to only do zip if there is subdirectories and in all other cases just upload the files as is.
Zenodo preview for eg. pdf, csv etc does not work if its in a zip file so ziping should be a last resort when the payload contains subdirectories.