* move APIs in util into namespace milvus
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* fix clang-format
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

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

* combine BlockingQueue.h and src/utils/BlockingQueue.inl
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>

* retry ci
Signed-off-by: Nyudong.cai <yudong.cai@zilliz.com>