set importer to check to see if local version is the same

[markmacgillivray]

when a user imports a file, it is stored locally in store/raw - when a file is imported again, should check to see if it is different. presumably it will be, but this will also be required when we enable scheduling automated checks of web urls. so need to do this anyway,

[markmacgillivray]

working on this. can pull the last-modified, and the local file creation date and compare. just need to get the comparison of different date formats to work cleanly.

[rufuspollock]

IMO this is very low priority (what is the user story this is needed for?).

I've also removed as part of the refactor the local storage functionality for the present since it seemed to add a lot of complexity for not much benefit (I understand you want to do asynchronous processing at some point but I think we should cross that bridge when we come to it). Happy to reinstate as needed but I'd recommend leaving until this is essential.

[markmacgillivray]

dropping this issue now. not storing local files.