pmem2: add asynchronous memcpy

.cirrus.yml

doc/Makefile

doc/libpmem2/.gitignore

doc/libpmem2/pmem2_config_set_vdm.3

doc/libpmem2/pmem2_get_memmove_fn.3.md

doc/libpmem2/pmem2_memcpy_async.3.md

src/Makefile

src/PMDK.sln

src/common.inc

src/common/Makefile

src/common/libpmemcommon.vcxproj

src/core/libpmemcore.vcxproj

src/core/membuf.c

src/core/membuf.h

src/core/pmemcore.inc

src/deps/Makefile

src/deps/miniasync/Libminiasync.vcxproj

src/deps/miniasync/Makefile

src/examples/examples_debug.props

src/examples/examples_release.props