Quantized Model for Torchscript

[xingyueye]

Hello～ Do you have plan to support quantized models for torchscript?

[tpoisonooo]

Work In Progress.

It is very likely not to use torch directly, we need convert it to onnx first, quantize model based on static graph.

[tpoisonooo]

In dynamic graph, you define a tensor and slice it with []. It would be converted to gather opr. Not to mention if clause.

[tpoisonooo]

https://github.com/open-mmlab/mmdeploy/pull/476