writerfilter: remove unused WW8ResourceModelImpl

Change-Id: Ib95e4d543b8ee78127847ea0ed2409cb343b1463
writerfilter: remove unused resourceidmapperback

Change-Id: I53d899e7d1122e773ad50c6a49213b76a68e5454
writerfilter: remove unused xmistat

Change-Id: I9ac4cbea66123a58007dfce639964f546847a36f
writerfilter: remove unused resourceidmapper

Change-Id: I70299737ce00a43202aafc5451e6b275feda1caf