chore: remove apollo config center

[MasterKenway]

What this PR does:

Which issue(s) this PR fixes:
Fixes #

You should pay attention to items below to ensure your pr passes our ci test
We do not merge pr with ci tests failed

• All ut passed (run 'go test ./...' in project root)
• After go-fmt ed , run 'go fmt project' using goland.
• Golangci-lint passed, run 'sudo golangci-lint run' in project root.
• After import formatted, (using imports-formatter to run 'imports-formatter .' in project root, to format your import blocks, mentioned in CONTRIBUTING.md above)
• Your new-created file needs to have apache license at the top, like other existed file does.
• All integration test passed. You can run integration test locally (with docker env). Clone our dubbo-go-samples project and replace the go.mod to your dubbo-go, and run 'sudo sh start_integration_test.sh' at root of samples project root. (M1 Slice is not Support)

[codecov-commenter]

Codecov Report

Merging #1932 (d574f14) into 3.0 (0ccec74) will decrease coverage by 0.64%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##              3.0    #1932      +/-   ##
==========================================
- Coverage   45.05%   44.40%   -0.65%     
==========================================
  Files         287      284       -3     
  Lines       17135    17027     -108     
==========================================
- Hits         7720     7561     -159     
- Misses       8598     8662      +64     
+ Partials      817      804      -13     

Impacted Files	Coverage Δ
config/reference_config.go	31.97% <0.00%> (ø)
config/config_center_config.go	14.28% <0.00%> (-58.10%)	⬇️
metadata/report/delegate/delegate_report.go	26.49% <0.00%> (-15.90%)	⬇️
remoting/xds/client.go	53.23% <0.00%> (+0.76%)	⬆️

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