Closes #2973, closes #3895, follow-up to espressomd/docker#190

Due to their fast release cycle, ROCm packages are not stable enough for ESPResSo. We are currently supporting ROCm 3.0 to 3.7, which means supporting two compilers (HCC and HIP-Clang) and keeping patches for each ROCm release in our codebase.  Maintaining these patches and the CMake build system for ROCm is time-consuming. The ROCm job also has a tendency to break the CI pipeline (#2973), sometimes due to random or irreproducible software bugs in ROCm, sometimes due to failing hardware in both the main CI runner and backup CI runner. The frequency of false positives in CI is too large compared to the number of true positives. The last true positives were 5da80a9 (April 2020) and #2973 (comment) (July 2019). There are no known users of ESPResSo on AMD GPUs according to the [May 2020 user survey](https://lists.nongnu.org/archive/html/espressomd-users/2020-05/msg00001.html). The core team has decided to drop support for ROCm ([ESPResSo meeting 2020-10-20](https://github.com/espressomd/espresso/wiki/Espresso-meeting-2020-10-20)).

The Intel image cannot be built automatically in the espressomd/docker pipeline. Re-building it manually is a time-consuming procedure, usually several hours, due to long response time from the licensing server and the size of the Parallel Studio XE source code. When a new Intel compiler version is available, it usually requires the expertise of two people to update the dockerfile. The core team has decided to remove the Intel job from CI and use the Fedora job to test ESPResSo with MPICH.