cmake: Import HDF5 in installed Legion
Otherwise we hit:
CMake Error at src/CMakeLists.txt:28 (add_library):
Target "ResilienceStatic" links to target "hdf5::hdf5-shared" but the
target was not found. Perhaps a find_package() call is missing for an
IMPORTED target, or an ALIAS target is missing?
In applications that use Legion but don't include their own copy of HDF5.