Feature issue #4402 finish router get example

[changsongl]

This is not finished yet. I just write a quick demo for how to implement this feature for issue #4402. I may have some details to think about, but I just wanna make sure the implementation is ok. I post demo below.

type MyController struct {
	web.Controller
}

func (m MyController) Ping() {
	m.Ctx.Output.Body([]byte("hello world"))
}

func main() {
	web.RouterGet("/ping", MyController.Ping)
	web.Run(":8090")
}

http://127.0.0.1:8090/ping
hello world

@flycash @jianzhiyao

[codecov-io]

Codecov Report

Merging #4416 (40d3954) into develop (82164e8) will increase coverage by 0.23%.
The diff coverage is 88.48%.

@@             Coverage Diff             @@
##           develop    #4416      +/-   ##
===========================================
+ Coverage    52.43%   52.66%   +0.23%     
===========================================
  Files          225      225              
  Lines        17237    17344     +107     
===========================================
+ Hits          9038     9135      +97     
- Misses        7272     7278       +6     
- Partials       927      931       +4     

Impacted Files	Coverage Δ
server/web/router.go	67.35% <84.33%> (+1.58%)	⬆️
server/web/server.go	14.97% <87.50%> (+5.61%)	⬆️
server/web/namespace.go	59.06% <100.00%> (+11.19%)	⬆️
server/web/session/sess_mem.go	30.58% <0.00%> (+2.35%)	⬆️

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[flycash]

@changsongl 我在原来的issue之下comment了一下，你可以看一下。

这个PR其实很不错，不过还可以弄得更好，虽然风险会更大。你可以考虑给我发封邮件，留个微信号，我们可以线下沟通一番。

[jianzhiyao]

checked @flycash

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
1.4% Duplication

[hhstu]

什么时间 release？