Prevent name duplication inside a datasource

Hello @bbrancot

Following issue #238 (closed), I think it would be important to avoid duplications of the name of virus/host inside the same data source. I do not think it will happen often that users have the exact same name for 2 virus/host, because it is unpractical for them, but I think mistakes like I did can be possible and create unwanted duplications.

So, I think during the uploading/updating/renaming process, a check should be done, and if there are duplicates inside the same virus/host, it should stop the process, and tell the user that duplications are not permitted and he should give specific name to each host/virus.

Is that feasible?