[Suggestion] Path options for textures in project files

[hibiii]

I've noticed that bbmodel files save an absolute path, a relative path to image files, and also the image itself in base64. This is fine for a personal project that won't leave your computer, but I feel like there should be an option, because Blockbench works fine with just a relative path saved. I assume it'll also work with just the absolute path, or just the image data.

One of the mods I'm working on, I'm pushing the bbmodel but I have to put a notice to remove the absolute path and the image data for the textures because the image will exist for the mod itself, regardless of the project file. It's also good practice not to duplicate data.

I suggest a set of options to be saved per project file that tell Blockbench what part of textures it should or should not save, in this case I'd tick relative paths but untick absolute paths and image data.

[JannisX11]

Related to #907