tests: port tests to tmt
    
    In this commit we:
    
    1. Use `tmt tests import` to gather all related
       metadata from tests/Support-local-additions-to-magic-files
       and tests/command-line-options directories and
       convert them into tmt format.
    2. Add missing requirement for bzip2 in
       tests/command-line-options/{Makefile,main.fmf}
       files.
    3. Replace an obsolescent `egrep` with a `grep -E`
       command in the tests/command-line-options/runtest.sh
       file.
    4. Create new tests/file-tests/Makefile file.
    5. Use `tmt tests import` to convert the
       tests/file-tests and all related
       metadata into tmt format.
    6. Simplify and update tests/file-tests/{prepare.sh,
       runtest.sh,reference.sh,readfile.py} scripts.
       Thank you lzaoral!
    7. Update and create new "references" (file-5.42.4 outputs)
       in the file-tests/reference.
    8. Rename the file-tests/blacklist.txt to
       file-tests/blocklist.txt.
    9. Replace the tests/tests.yml file with
       the plans/file-CI-plan.fmf file.