Added support For S3 drop folders:
   1. Implemented kFileTransferManager->doModificationTime, doFileSize, doListFileObjects for S3 manger.
   2. Added S3 into admin console form
   3. Added S3 into Drop folder API Object
   4. Added S3 enums for Drop folder plugin
   5. Added S3 to KDropFolder Batch engine
   6. Added S3 string to the admin console combo box
Merge remote-tracking branch 'origin/IX-9.15.0' into IX-9.15.0