With the end goal of simplifying ownership and memory management,
and allowing the use of `get_name` in contexts without statically
allocated strings, use `std::string` for the return values of these two
operator type callbacks instead of `const char *` and `char *`.
In the meantime things get uglier in some places. I'd expect `std::string`
to be used more in the future elsewhere in Blender though.
Pull Request: https://projects.blender.org/blender/blender/pulls/110823
f0467b4615