HPCC-10093 Read compressed file size from DFU attributes

In this fix, WsDFU DFUInfo/DFUQuery reads compressed file size from DFU attributes.
The compressed file size can be shown on EclWatch file browser and details page.

This fix also sets a file to be compressed if the file is an index because all of
indexes are compressed.

Signed-off-by: Kevin Wang kevin.wang@lexisnexis.com