Add HDF5 2.1.1 container image and CI workflow

Mirrors the HDF5 2.0.0 setup. New ubuntu-24.04-hdf5-2.1.1 Dockerfile
based on Ubuntu 24.04, building HDF5 2.1.1 from the GitHub release
tarball with the same parallel + threadsafe + allow-unsupported flags
used for 2.0.0. New h5bench-hdf5-2.1.1.yml workflow consumes
hpcio/hdf5-2.1.1 and runs the same SYNC + ASYNC suite as the 2.0.0
job.

The image needs to be built and pushed to hpcio/hdf5-2.1.1 before the
workflow can go green.

Author: jeanbez