[ntuple] Add a common `RNTupleOpenSpec` #12812

Job	Run time
mac13 ARM64 LLVM_ENABLE_ASSERTIONS=On, builtin_zlib=ON	33m 58s
fedora39 LLVM_ENABLE_ASSERTIONS=On, CMAKE_CXX_STANDARD=20	1h 55m 57s
mac14 X64 LLVM_ENABLE_ASSERTIONS=On, CMAKE_CXX_STANDARD=20	1h 9m 23s
Windows 10 x64 Release	2h 36m 14s
mac15 ARM64 LLVM_ENABLE_ASSERTIONS=On, CMAKE_CXX_STANDARD=20	37m 16s
alma8 LLVM_ENABLE_ASSERTIONS=On	1h 21m 16s
Windows 10 x86 Release	1h 7m 49s
Upload Event Payload	2s
alma9 LLVM_ENABLE_ASSERTIONS=On, CMAKE_BUILD_TYPE=Debug	2h 3m 20s
mac-beta ARM64 LLVM_ENABLE_ASSERTIONS=On, CMAKE_CXX_STANDARD=20	38m 19s
ubuntu20 LLVM_ENABLE_ASSERTIONS=On	1h 31m 7s
ubuntu22 imt=Off, LLVM_ENABLE_ASSERTIONS=On, CMAKE_BUILD_TYPE=Debug	2h 4m 22s
ubuntu2404 LLVM_ENABLE_ASSERTIONS=On, CMAKE_BUILD_TYPE=Debug	2h 17m 51s
debian125 LLVM_ENABLE_ASSERTIONS=On, CMAKE_CXX_STANDARD=20	1h 28m 37s
alma9 modules_off runtime_cxxmodules=Off	50m 2s
alma9 march_native CMAKE_BUILD_TYPE=RelWithDebInfo, CMAKE_CXX_FLAGS=-march=native, CMAKE_C_FLAGS=-march=native, fortran=OFF	1h 16m 53s
alma9 arm64 CMAKE_BUILD_TYPE=RelWithDebInfo, ccache=ON	47m 8s
alma9-clang clang LLVM_ENABLE_ASSERTIONS=On, CMAKE_C_COMPILER=clang, CMAKE_CXX_COMPILER=clang++	46m 53s
	23h 6m 27s

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