feat: prettier ear/tail mutation graphics

[scarf005]

Summary

SUMMARY: Content "Prettier ear/tail mutation graphics"

Purpose of change

• resolves ☂️ anime kemonomimi ear mutations #3202
• resolves add alternative ear mutation to external tileset #3267

Describe the solution

drew new sprites for animal ear and tail mutation. (mouse ear drawn by @NobleJake)

Describe alternatives you've considered

enjoy old graphics

Testing

Additional context

[Zireael07]

The ears are not noticeably prettier (hard to judge at those sizes) BUT they moved from where a person has ears to top of head

[chaosvolt]

Where the ears should go is a bit of a meme, but I think it does accomplish an improvement to recognition. You can actually tell it's an ear an not a weird horn. Tails also seem not changed much but having them on the same side is probably good for consistency.

EDIT: Relevant to that first bit:

[chaosvolt]

Also might be worth adding to the documentation before I inevitably forget.

This also reminds me that I could probably afford to split the main image's contents up into separate images containing related content (like one for shields or wearables in general, one for furniture, one for monsters, etc), since it'd make it easier to tell at a glance what the external tileset is adding stuff to, and make it more likely that two people will be able to work on separate PRs without running into each other's efforts.

[scarf005]

done.

[scarf005]

...hecc