add scripts to run test suite after build job has finished

[trz42]

First outline of how testing could be added to build-and-deploy procedure. See also accompanying PR for the bot (EESSI/eessi-bot-software-layer#222).

This PR adds three scripts:

• bot/test.sh prepares the environment for running the tests inside the build container
  • because it runs on the same node (in fact, the same job) that was building software packages, it tries to re-use the existing temporary storage (e.g., cached CernVM-FS data, and particularly the fuse-overlayfs upper directory): directly or from a tarball of the build step
  • alternatively, it might unpack or bind mount built software from the tarball containing the software installation
  • the script is largely similar to bot/build.sh and bot/inspect.sh (for the latter see script to more easily inspect a build job #317)
• run_tests.sh is just a small script that runs test_suite.sh in a compat layer environment (very similar to install_software_layer.sh)
• test_suite.sh runs some tests
  • at the moment it runs eb --sanity-check-only for all easyconfigs that were "added" to an easystack file (by design, it will also process easyconfigs whose line has changed)
  • only changed easystack files are processed
  • the script is very similar to EESSI-pilot-install-software.sh

TODO:

• test that it works
• add script bot/check-test.sh that processes the result of the test(s) and produces and update to be added to the PR comment (job status table); this is likely somewhat similar to bot/check-build.sh

[eessi-bot]

Instance eessi-bot-mc-aws is configured to build:

• arch x86_64/generic for repo eessi-hpc.org-2023.06-compat
• arch x86_64/generic for repo eessi-hpc.org-2023.06-software
• arch x86_64/intel/haswell for repo eessi-hpc.org-2023.06-compat
• arch x86_64/intel/haswell for repo eessi-hpc.org-2023.06-software
• arch x86_64/intel/skylake_avx512 for repo eessi-hpc.org-2023.06-compat
• arch x86_64/intel/skylake_avx512 for repo eessi-hpc.org-2023.06-software
• arch x86_64/amd/zen2 for repo eessi-hpc.org-2023.06-compat
• arch x86_64/amd/zen2 for repo eessi-hpc.org-2023.06-software
• arch x86_64/amd/zen3 for repo eessi-hpc.org-2023.06-compat
• arch x86_64/amd/zen3 for repo eessi-hpc.org-2023.06-software
• arch aarch64/generic for repo eessi-hpc.org-2023.06-compat
• arch aarch64/generic for repo eessi-hpc.org-2023.06-software
• arch aarch64/neoverse_n1 for repo eessi-hpc.org-2023.06-compat
• arch aarch64/neoverse_n1 for repo eessi-hpc.org-2023.06-software
• arch aarch64/neoverse_v1 for repo eessi-hpc.org-2023.06-compat
• arch aarch64/neoverse_v1 for repo eessi-hpc.org-2023.06-software

[boegel]

note: got merged via larger PR #467 that includes these commits