* support GPUIVF delete
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* calc bitset offset correctly
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* support GPUSQ8 delete
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* support GPUIVFPQ delete
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* update unittest for GPU delete
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* delete FAISS compile option -DFAISS_USE_FLOAT16
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* code opt
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* update changelog
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>