Extend/delete support for harvest lists

[mqrause]

Summary

Infrastructure "Extend/delete support for harvest lists"

Purpose of change

Fixes #75958
Fixes #61525

Describe the solution

Add and use harvest_entry_reader. Readers apparently can't handle std::list containers, so I changed the harvest_list::entries_ member to std::vector.
Since the equality check for harvest entries only checks the drop member, giving that should be enough for delete.
Also changed the rabbit_with_skull harvest to copy-from mammal_small_fur and extend with the skull to test functionality.

Describe alternatives you've considered

Testing

Butchered a rabbit to check results.

Additional context

Result of full butchery of mon_rabbit

[Karol1223]

This solves #61525