Enable all `modernize-*` checks in clang-tidy configuration

[msimberg]

https://clang.llvm.org/extra/clang-tidy/checks/list.html. This can be done piecewise, one check at a time.

-DCMAKE_CXX_CLANG_TIDY=clang-tidy;--fix;--fix-errors is very useful for this (remember to build with a single job).

This is a great issue for someone interested in contributing to pika.