[DUBBO-3137]: step4 - remove ConfigConstants

[CrazyHZM]

What is the purpose of the change

issue #3137: step4 - remove ConfigConstants

Brief changelog

XXXXX

Verifying this change

XXXXX

Follow this checklist to help us incorporate your contribution quickly and easily:

• Make sure there is a GITHUB_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GITHUB issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Format the pull request title like [Dubbo-XXX] Fix UnknownException when host config not exist #XXX. Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Run mvn clean install -DskipTests=false & mvn clean test-compile failsafe:integration-test to make sure unit-test and integration-test pass.
• If this contribution is large, please follow the Software Donation Guide.

[codecov-io]

Codecov Report

Merging #4079 into master will increase coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4079      +/-   ##
============================================
+ Coverage     62.91%   62.98%   +0.06%     
- Complexity      542      544       +2     
============================================
  Files           756      756              
  Lines         32541    32581      +40     
  Branches       5137     5164      +27     
============================================
+ Hits          20474    20520      +46     
+ Misses         9703     9701       -2     
+ Partials       2364     2360       -4

Impacted Files	Coverage Δ	Complexity Δ
...apache/dubbo/rpc/protocol/dubbo/DubboProtocol.java	66.91% <ø> (+0.12%)	0 <0> (ø)	⬇️
...va/org/apache/dubbo/config/ConfigCenterConfig.java	77.61% <ø> (ø)	0 <0> (ø)	⬇️
.../java/org/apache/dubbo/config/ReferenceConfig.java	59.85% <ø> (ø)	0 <0> (ø)	⬇️
...ava/org/apache/dubbo/config/ApplicationConfig.java	97.59% <ø> (ø)	0 <0> (ø)	⬇️
...ain/java/org/apache/dubbo/config/ModuleConfig.java	89.47% <ø> (ø)	0 <0> (ø)	⬇️
...n/java/org/apache/dubbo/config/RegistryConfig.java	91.5% <ø> (ø)	0 <0> (ø)	⬇️
...in/java/org/apache/dubbo/config/ServiceConfig.java	58.2% <ø> (ø)	0 <0> (ø)	⬇️
...ain/java/org/apache/dubbo/config/MethodConfig.java	95.12% <ø> (ø)	0 <0> (ø)	⬇️
...n/java/org/apache/dubbo/config/ProtocolConfig.java	92.85% <ø> (ø)	0 <0> (ø)	⬇️
...g/apache/dubbo/config/AbstractInterfaceConfig.java	72% <ø> (ø)	0 <0> (ø)	⬇️
... and 32 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 228cad5...cbda1fa. Read the comment docs.

[beiwei30]

LGTM.