hwloc 2.0 breaks topo class and cannot be used

[biddisco]

We need to put in a cmake check for the hwloc version and give the user a warning or error if they try to use hwloc 2.0 with HPX.

(The topology of numa/memory and cores changes with hwloc 2 and it breaks the way we assign cores/etc).

[biddisco]

NB. This issue duplicates #3161

[hkaiser]

This is a duplicate for #3161

[biddisco]

The fix applied to #3161 only solved the building and not the execution of HPX with hwloc 2

[hkaiser]

This was fixed by merging #3225