chore: provide post content retrieval bean for plugins

[guqing]

What type of PR is this?

/kind improvement
/area core
/area plugin
/milestone 2.16.x

What this PR does / why we need it:

为插件提供文章内容获取的 bean 以简化文章内容获取

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?

为插件提供文章内容获取的 Bean

[sonarcloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.2% Duplication on New Code

See analysis details on SonarCloud

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 25.00000% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 56.64%. Comparing base (5fdf6c0) to head (4c80d22).
Report is 202 commits behind head on main.

Files	Patch %	Lines
...a/run/halo/app/content/PostContentServiceImpl.java	16.66%	15 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5981      +/-   ##
============================================
- Coverage     56.91%   56.64%   -0.27%     
- Complexity     3319     3477     +158     
============================================
  Files           587      612      +25     
  Lines         18968    20543    +1575     
  Branches       1401     1419      +18     
============================================
+ Hits          10795    11636     +841     
- Misses         7594     8329     +735     
+ Partials        579      578       -1     

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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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