Update CI to AlmaLinux9 and LCG_104
This updates the CI to the new standard distribution for LXPLUS, RHEL9/AlmaLinux9.
- New CI jobs for AlmaLinux 9
- CentOS7 only as legacy build with GCC
- Now allowing
clang-tidy
andclang-format
>= 12, required one formatting change - Now always building with same C++ standard as the linked ROOT version, which is C++20 already in some cases
lint-diff fails because of external header includes. Will merge hard when approved.