View metadata on older version of a file

[lmarini]

Add ability to view metadata on an older version of a file. Right now both user and extracted metadata tabs are empty when a new version is added.

[longshuicy]

we need to investigate if we store all the metadata in the mongodb or just replace it with the latest one. @ddey2 could you put what you found here?

[ddey2]

As far as I am aware, we keep one metadata with every file and keeps on updating the version along with it.

If a file doesn't have current version metadata, we show the last file version metadata.

[ddey2]

Expected behavior:
For user metadata - it should show last available version metadata (bug #348 needed to be fixed)
for extractor metadata - it should automatically trigger extractor on updating a file

[longshuicy]

for user metadata; maybe find a way to associate past file version with past user generated metadata