Make protobuf generated api file under same package with .proto

[hzxuzhonghu]

What would you like to be added:

Currently we make the https://github.com/kmesh-net/kmesh/tree/main/api/workloadapi generated files into https://github.com/kmesh-net/kmesh/tree/main/api/v2/workloadapi. It does work well from fdunctionality, in my local dev IDE, goland/vscode, the code navigation does not work well, when i want to naviagate to

kmesh/api/v2/workloadapi/workload.pb.go

Line 707 in 52d8f9e

type Workload struct {

, but it jump to

kmesh/api/workloadapi/workload.proto

Line 138 in 52d8f9e

message Workload {