v0.6.0 - Depth model support

Added support for the StabilityAI SD depth model using the scene depth as a guide for performing depth2img image generation (see the model card page for more information about this technique).

Any model loaded with the Depth parameter set to true will expose the depth panel in the plugin UI. Use the scene depth scale to set how much of the scene will be visible in the captured depth map. Use the Diffusers_StabilityAI2-1_depth model as a starting point.

Full Changelog: v0.5.6...v0.6.0