MOBILESDK-4 Use random filenames in server side. This way, test environment doesn’t get corrupted if cleaup is not successfully completed

@jmnavarro I still need to check why fileSize doesn't match self.progress. It shouldn't be hard coded like that, mine gives now 44302, yours gives 44288 and before it was 44214 bytes.

I think it may be related to the total request size, it may be adding up the headers size to the file size.