- use FIND_PACKAGE(LIBAIO) to find libaio
- Use standard CMake conventions in Find{PMEM,URING}.cmake
- Drop the LIB from LIB{PMEM,URING}_{INCLUDE_DIR,LIBRARIES}
  It is cleaner, and consistent with how other packages are handled in CMake.
  e.g successful FIND_PACKAGE(PMEM) now sets PMEM_FOUND, PMEM_LIBRARIES,
  PMEM_INCLUDE_DIR, not  LIBPMEM_{FOUND,LIBRARIES,INCLUDE_DIR}.
- Decrease the output. use FIND_PACKAGE with QUIET argument.
- for Linux packages, either liburing, or libaio is required
  If liburing is installed, libaio does not need to be present   .
  Use FIND_PACKAGE([LIBAIO|URING] REQUIRED) if either library is required.