chore: reorganize package structure in application project

[guqing]

What type of PR is this?

/milestone 2.20.x
/area core

What this PR does / why we need it:

整理 application 项目的包结构

Does this PR introduce a user-facing change?

None

[sonarcloud]

Quality Gate failed

Failed conditions
3 Security Hotspots
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarCloud

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[JohnNiang]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JohnNiang

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• OWNERS [JohnNiang]

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 58.14%. Comparing base (6cd8dc8) to head (792e0dd).
Report is 82 commits behind head on main.

Files with missing lines	Patch %	Lines
...in/java/run/halo/app/theme/service/ThemeUtils.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6691      +/-   ##
============================================
- Coverage     58.18%   58.14%   -0.04%     
- Complexity     3774     3942     +168     
============================================
  Files           651      679      +28     
  Lines         22125    23216    +1091     
  Branches       1538     1582      +44     
============================================
+ Hits          12873    13500     +627     
- Misses         8641     9092     +451     
- Partials        611      624      +13     

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