Support LoRA and Control Net in Stable Diffusion demo (#18593)
### Description
(1) Export onnx model with LoRA weights for both SD 1.5 and SDXL
(2) Export onnx model with Control Net for both SD 1.5 and SDXL. For SD
1.5, it is allowed to use multiple control nets. For SDXL, at most one
control net is supported right now.
(3) Add demo of LCM LoRA
(3) Add demo of control net.