Fix tacc docker image workflow

[gassmoeller]

Our docker image for the TACC systems has been broken for a while: https://github.com/geodynamics/aspect/actions/workflows/docker.yml.

This PR fixes a few issues to fix the workflow:

• update to a newer base image with a supported ubuntu version
• fix an issue with the GPG key of the intel MPI repo
• update deal.II version
• split stages for compiling deal.II and dependencies (mostly for convenience when debugging the build process)
• disable ASPECT examples

I had to disable the ASPECT examples, because I couldnt get them to compile as part of the general build process. They would always try to use the non MPI compiler and fail with:

make[1]: *** [CMakeFiles/Makefile2:1949: benchmarks/diffusion_of_hill/CMakeFiles/analytical_topography.dir/all] Error 2
In file included from /opt/deal.II-v9.6.0/include/deal.II/base/mpi.h:18,
                 from /opt/aspect/include/aspect/global.h:28,
                 from /opt/aspect/include/aspect/material_model/interface.h:24,
                 from /opt/aspect/include/aspect/material_model/simple.h:24,
                 from /opt/aspect/benchmarks/finite_strain/../../cookbooks/finite_strain/finite_strain.cc:21,
                 from /opt/aspect/benchmarks/finite_strain/finite_strain.cc:20:
/opt/deal.II-v9.6.0/include/deal.II/base/config.h:606:12: fatal error: mpi.h: No such file or directory
  606 | #  include <mpi.h>
      |            ^~~~~~~
compilation terminated.

I am pretty sure this is somehow related to dealii/candi#207 but no matter how I set USE_DEAL_II_CMAKE_MPI_COMPILER the problem persists. Additionally, if I start the resulting docker image and manually compile the example plugins everything works fine, so it is only related to using DASPECT_INSTALL_EXAMPLES=ON in the full ASPECT build process. After a few hours of digging through the problem I gave up and decided to disable compiling the examples. I think this is fair, because the use case of this image is to run large-scale models on the TACC systems, not to make it easy to run our examples.