feat(registry): support discovery registry center

[yeqown]

Description (what this PR does / why we need it):

• support discovery registry center
• add example for using discovery registry center

Which issue(s) this PR fixes (resolves / be part of):

resolves #1472

Other special notes for reviewer:

I need some time to refactor code style, any advices and code review can help this work, thanks ~

[codecov-commenter]

Codecov Report

Merging #1480 (a00bcfe) into main (24ec23f) will increase coverage by 0.10%.
The diff coverage is n/a.

❗ Current head a00bcfe differs from pull request most recent head 65243a4. Consider uploading reports for the commit 65243a4 to get more accurate results

@@            Coverage Diff             @@
##             main    #1480      +/-   ##
==========================================
+ Coverage   66.65%   66.76%   +0.10%     
==========================================
  Files          66       66              
  Lines        3038     3033       -5     
==========================================
  Hits         2025     2025              
+ Misses        841      836       -5     
  Partials      172      172              

Impacted Files	Coverage Δ
transport/http/calloption.go	100.00% <0.00%> (+15.62%)	⬆️

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[daemon365]

feat #1472

[yeqown]

review plz ~

[longXboy]

Why not quote the original bilibili/discovery SDK and wrap it to implement kratos interface instead of copying the code？

[yeqown]

@longXboy

1. The old package（discovery/naming） imports kratos@v1 package, it's not wise to use old version of kratos. https://github.com/bilibili/discovery/blob/1e12d5c0080ecd7ce97ab78076ef36dda8d56a1a/naming/client.go#L16-L19
2. Personal preference: the old package use std http client which is no friendly to human and makes the code fetid and wordy.
3. I'm not sure of that is it workable wraps bilibili/discovery SDK to implement kratos@v2 registry.Registrar and registry.Discovery interfaces.

[longXboy]

@longXboy

1. The old package（discovery/naming） imports kratos@v1 package, it's not wise to use old version of kratos. https://github.com/bilibili/discovery/blob/1e12d5c0080ecd7ce97ab78076ef36dda8d56a1a/naming/client.go#L16-L19
2. Personal preference: the old package use std http client which is no friendly to human and makes the code fetid and wordy.
3. I'm not sure of that is it workable wraps bilibili/discovery SDK to implement kratos@v2 registry.Registrar and registry.Discovery interfaces.

LGTM