BUG Upload: file versioning uses illegal underscore in filename

Bug:
Uploaded files without a suffix can not be found in filesystem because file versioning appends an underscore to the filename which is filtered out by FileNameFilter in File->setName().

Refactoring:
- explode('.', 'UploadTest-testUpload.tar.gz')
- use first array value "UploadTest-testUpload" to version the file to "UploadTest-testUpload2"
- append the rest of the array again: "UploadTest-testUpload2.tag.gz"

Also:
- removed .tar.gz/.tar.bz2 exception -- covered by see above
- removed underscore exception -- covered by FileNameFilter

#2904