Move lua libraries to their own directory.

include/lua/info.h

include/lua/init.h

include/lua/slab.h

include/lua/stat.h

include/lua/uuid.h

mod/CMakeLists.txt

src/CMakeLists.txt

src/admin.m

src/admin.rl

src/box/CMakeLists.txt

src/box/box_lua.m

src/lua/info.m

src/lua/init.m

src/lua/slab.m

src/lua/stat.m

src/lua/uuid.m

src/tarantool.m