Remove outdated plugins from Hub
Description
Some plugins in Hub are outdated and no longer required. For example, there is a "Batch File Sink" plugin that is no longer useful now that there is a 'File' sink bundled in core-plugins that has additional functionality. The same is true for the "Whole File Reader", which is replaced by the 'blob' format in the File source.
Release Notes
Removed the outdated Batch File Sink and Whole File Reader plugins from Hub. These can be replaced by the File sink and source that are already pre-packaged with CDAP.
