[clang-tidy] Add option to ignore user-defined literals in readability-magic-numbers

Some user-defined literals operate on implementation-defined types, like
"unsigned long long" and "long double", which are not well supported by
this check. Currently, the check gives warnings when using UDLs, without
giving possiblity to the user to whitelist common UDLs. A good compromise
until a proper fix is found (if any) is to allow the user to disable
warnings on UDLs.

Partially fixes #61656

Differential Revision: https://reviews.llvm.org/D146913