Expand autocomplete system to support custom tags & filenames

[space-nuko]

For embeddings and LoRAs that can be inserted into the conditioning prompts, the autocomplete could show results for valid filenames using those systems

https://github.com/skfoo/ComfyUI-Coziness

For a start embeddings can be supported somewhat easier since they're built-in to ComfyUI. How to integrate this with external node types can be trickier. It might be worth looking into if ComfyUI can provide a endpoint for such keywords instead of maintaining separate support in ComfyBox