[clang-tidy] add IgnoreMacros option to modernize-use-equals-delete
And also enable it by default to be consistent with e.g. modernize-use-using.
This improves consistency inside the check itself as well: both checks are now
disabled in macros by default.
This helps e.g. when running this check on client code where the macro is
provided by the system, so there is no easy way to modify it.
Reviewed By: alexfh
Differential Revision: https://reviews.llvm.org/D53217