[Enhancement] refactor the proxy server with spi implementions

[xiaoma20082008]

Before Creating the Enhancement Request

• I have confirmed that this should be classified as an enhancement rather than a bug/feature.

Summary

1. create an interface with name ProxyServer to make the grpc/http/remoting interface more abstract
2. create an spi interface with name ProxyServerFactory to build ProxyServer

Motivation

The ProxyStartup class is too confused to understand

Describe the Solution You'd Like

use Java's SPI to solve this

Describe Alternatives You've Considered

Or use a new spi like dubbo

Additional Context

No response