Add an API to estimate peak VRAM usage of a model

[RunDevelopment]

Add an API for estimating the peak VRAM usage of a model. Ideally, this would be something simple like:

class ImageModelDescriptor:
    ...
    def estimate_peak_memory(self, size: tuple[int, int]) -> int | None:
        """
        Returns an estimate for the peak memory usage (VRAM if on the GPU) of the model for the given image size.

        If no estimate is available, `None` will be returned.
        """

This would allow us to use better VRAM estimates in chaiNNer, which would allow us to pick better tile sizes.

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As for actually finding good estimates. I think we could use a script to determine an estimate automatically. The script would be given an architecture, possible hyperparameters, and a series of image size to test. It would then simply run a model on a random image and measure the peak VRAM usage for all combinations of images sizes and hyperparameters. This gives us some data points to work with. The rest is a curve-fitting exercise, and generating python code for what we could out.

With this script in place, we can just run it and automatically get a good function for estimating the VRAM usage of an architecture.