Fix overconstrained HDF5 variants (#29132)

* hdf5: mark +fortran+shared conflict for older version

This version was only activated unintentionally by silo's conflict
statement, but `@1.8.15+shared+fortran+cxx` errors out in configure:

```
CMake Error at CMakeLists.txt:814 (message):
   **** Shared FORTRAN libraries are unsupported ****
```

* silo: refine hdf5 conflicts to avoid building old version

Before this, `silo+hdf5` concretized to 1.10.7 or sometimes 1.8.15. Now
I've verified it works for the following configurations:
```
silo@4.10.2 patches=7b5a1dc,952d3c9
^   hdf5@1.10.7 api=default

silo@4.10.2 patches=7b5a1dc,952d3c9,eb2a3a0
^   hdf5@1.10.8 api=v18

silo@4.10.2 patches=7b5a1dc,952d3c9,eb2a3a0
^   hdf5@1.12.1 api=v110

silo@4.11-bsd patches=eb2a3a0
^   hdf5@1.12.1 api=v110

silo@4.11-bsd patches=eb2a3a0
^   hdf5@1.10.8 api=default

silo@4.11-bsd patches=eb2a3a0
^   hdf5@1.12.1 api=default
```

and verified that the following fail:
```
silo@4.10.2 ^hdf5@1.12.1 api=default
silo@4.11 ^hdf5 api=v18
silo@4.11-bsd ^hdf5@1.13.0 api=v12
silo@4.11-bsd ^hdf5@1.13.0 api=default
```

and have updated the constraints to match. Hdf5 no longer has to be
downgraded to work with Silo.

* silo: fix dependency conflicts

* py-h5py: shorten and add comments to py-h5py hdf5 dependencies

* e4s: remove slightly outdated hdf5 requirement

* e4s: remove excessive hdf5 variant constraints

These I think are holdovers from the old concretizer.

- `hdf5_compat` can be expressed as `+hdf5 ^hdf5@1.8`
- The extra variants on hdf5 shouldn't break conduit
- axom unnecessarily restricts hdf5 version

* conduit: restore hdf5_compat flag

share/spack/gitlab/cloud_pipelines/stacks/e4s/spack.yaml

@@ -33,8 +33,6 @@ spack:
       variants: +bzip2 ~nls +xz
     hdf5:
       variants: +fortran +hl +shared
-      version:
-        - 1.10.7
     libfabric:
       variants: fabrics=sockets,tcp,udp,rxm
     libunwind: