Clang-tidy upgrade

[cattabiani]

Currently we use clang-tidy-7 which relies on python 2. Since we want to drop python 2 we should upgrade clang-tidy to a newer version

[tristan0x]

• Run ClangTidy 7 with the default configuration providing by this project on several projects to see if it is not too much pedantic. Projects should be at least basalt, nmodl, and coreneuron
• The CMake code that handles ClangTidy configuration file should behave the same than with ClangFormat: one file per version.
• Run at least ClangTidy 9, and ClangTidy 11 on the projects mentioned above in order to create and adjust the config files .clang-tidy-9 and .clang-tidy-11