gitignore and cleanup in the mCBM2021 macro folder

• Add general git ignore filter for all_XXXX.par files in all mcbm macro folders until 2099 (original idea by @karpushkin_AT_inr.ru
• Same for core dumps created when segfault in "bash" ROOT session
• Same for PDF files
• Add gitignore for private ROOT settings in mcbm2021 folder
• Remove existing private ROOT config in mcbm2021 folder

added mCBM label

approved this merge request

Dear @f.uhlig, @p.-a.loizeau,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label

merged