*sigh* Added usage policy

Because it has become necessary for me to do so, I have added a usage policy to all my asset packs. This comes in the form of a notice on the itch page, and a more detailed README included in each pack. For your convenience, here is what that README contains:

Thanks for downloading my asset pack!

...unless you're planning to use it for any of the following:

• training AI
• anything that is AI-generated
• anything that utilizes AI-generated content in any capacity
• anything that is hateful, demeaning, or otherwise negative towards any oppressed/marginalized people
• anything that is positive toward or at all supportive of anyone with the above views

...in which case, kindly delete all of my asset packs from your computer and fuck off.