Allow ControlNet Model File Selection

[adiadiadi333]

I think you have hardcoded to use a sd15 default controlnet model. Its causing error for sdxl checkpoints.

Exception: ControlNet model control_v11p_sd15_canny 2a78b57c is not compatible with sd model(StableDiffusionVersion.SDXL)

Can you pls add some UI or some comdline param args to change that? Even replacing another controlnet model with same name doesnt work.