Figura v5 support

This [Figura](/mod/figura) addon adds compatibility with Blockbench 5.0's updated model format. (and a few other nice things, too!) ## Do Not Use With Figura 0.1.6 it's built in to figura 0.1.6! adding both will prevent the game from launching ## rest of description These changes will mostly likely be included as part of the next major Figura update, as part of [PR #448](https://github.com/FiguraMC/Figura/pull/448). That might take a while to release; this addon serves as an interim solution. The code in this addon is the same as in the aformentioned pull request, along with a mixin to integrate the new code. ## Features! - Support for 5.0 model files (the main reason you're here) - Better error messages for animation keyframes (these are tied pretty closely into the importing process) - A fix for `require` that caused it to not work on Windows if the "name" of the code calling it has characters that would be illegal if used in the filesystem (notably, `?` is used in the improved animation keyframe changes) ## About 1.16.5 I don't really want to do the refactoring work to make the code work with Java 8 for this addon; it'll happen for Figura eventually, but unfortuately that means you can't use this addon on 1.16.5 (which uses Java 8.) ## Do I need this? > for all users - You **need to keep this addon installed** to continue to load models from the filesystem created with Blockbench 5.0.0 or later. - You **do not need this addon** to load avatars uploaded by other people with this addon. - You **do not need this addon** to load avatars that have been uploaded to the cloud by you using this addon in another instance (it only impacts compiling local avatars) - You **might need this addon** to use an avatar you downloaded from the internet. This is usually indicated if loading fails with a message like `Cannot invoke "..." because the return value of "..." is null`, but there are other reasons that error could appear as well. ## Do other people need this? - See point 2 above, and the section below. - **No** if you're just uploading your avatar to the Figura cloud. - **Yes** if you're sharing the avatar with other people as e.g. a `.zip` file. ## Mind the gap > for avatar creators - If you're sharing avatars you created, please either **stick to 4.12 for now**, or **make it very obvious that this addon is required**. This will hopefully prevent confusion from your users if they try to load your avatar and it doesn't work. ## Modpacks? Of course! (also it's MIT licensed, you don't need my permission for this)