Add file modified date column to file repositories

Files are often updated by users of repositories and often may upload a file with the same name as previously uploaded files. Going by name alone is problematic when determining which file should be used or which file can be deleted. This is especially problematic with the recent files repository which doesn't indicate which file it is pointing to if there are two known files of the same name recently accessed. I believe only one file with that name is shown in the recent files repository and does not differentiate between the two distinct files with the same name and file type. But perhaps that is a separate request. Added more detail about the file would be quite helpful for end users to manage their files.