Enhance the scalability of multi-type workloads

[chenzhiguo]

Describe the feature

Currently, KPA natively supports automatic scaling for workloads like Deployment. However, many large enterprises have their own developed types of workloads, such as the open-source CloneSet or mine AppSet. At this point, Knative has some shortcomings in scalability when facing different types of workloads. There is a hope to enhance scalability in this regard.