feat(cmd): support generate echo route based on protobuf

[sysulq]

Issue Description

Type: feature request

goos: linux
goarch: amd64
pkg: github.com/douyu/jupiter/pkg/server/xecho
cpu: Intel(R) Core(TM) i5-10500 CPU @ 3.10GHz
BenchmarkHTTP/HTTP_with_reflect-12                100808             14692 ns/op            9211 B/op         68 allocs/op
BenchmarkHTTP/HTTP_without_reflect-12             145160             13771 ns/op            8184 B/op         56 allocs/op
BenchmarkHTTP/HTTP_with_protojson-12              158428             13072 ns/op            8184 B/op         56 allocs/op
BenchmarkHTTP/HTTP_with_json-12                   265099              4733 ns/op            7448 B/op         34 allocs/op
BenchmarkHTTP/HTTP_with_gateway-12                 74196             36914 ns/op           10735 B/op        102 allocs/op
PASS
coverage: 23.2% of statements
ok      github.com/douyu/jupiter/pkg/server/xecho       10.081s

Consider the benchmark here, we won't use grpc-gateway, and try to simplify the implementation to satisfy current situation.
And maybe standard json should be nice after remove the emitempty from json tag.

Describe what feature you want

Additional context

Add any other context or screenshots about the feature request here.

[sysulq]

#696