Ensure duplicate tag/updating wording is clear

[baeolophus]

Check https://github.com/etag/etagq/blob/newupload/etagq/tasks/db_utils.py, line 243 for code logic

[baeolophus]

eef1fa0

[baeolophus]

based on comments from workshop2 user this still needs work. maybe add notice on upload page itself.
"My specific questions dealt with duplicate files uploading and being able to erase groups of files, or in R speak "clear the environment". "

[baeolophus]

workshop2 user comments: "It's not clear once you upload the data how to manage it once it's on the ETAG site. It would be nice if it were easier to select all or select some points (like in the RFID reads where there can be thousands of points) in the event that some items need to be deleted. Or maybe a really convenient way to delete duplicates if we don't want them (I know some people may want duplicates for their own reasons)."