added new generic files
renamed upload styles to generic UploadFilesView.less
added abstract file collection
updated jar list and jar file to inherit from generics
added license headers to new files
added drop filter to Upload Jars
added abstract files to DT module
renamed abstract file to upload file
added check for beforeUpload on collection
improved documentation of upload files view
Merge pull request #728 from andyperlitch/extract_upload.MLHR-812

Extracted upload functionality to base classes