Refactor project structure for a better development

[JohnNiang]

What type of PR is this?

/kind cleanup
/area core

What this PR does / why we need it:

This PR totally refactor project structure for a better plugin development. Now we can maintain and publish api and platform modules at Halo application side, which will be references by plugins.

Currently, we can execute command ./gradlew clean publish to publish api and platform modules into local Maven repository, so that we can refer these dependencies (run.halo.tools.platform:plugin:2.4.0-SNAPSHOT and run.halo.app:api:2.4.0-SNAPSHOT) in plugin projects.

I will make another pull request to publish api library and platforms into Maven central repository.

Modules explanation:

• API module contains common classes which might be used by plugins.
• Plugin Platform module contains dependency declarations of other plugin API modules.
• Application Platform module contains dependency declarations application module might uses.

If we want to build application only(exclude check and jar), we have to execute the command below:

./gradlew clean :application:build -x :application:check -x :application:jar

The executable Jar will be generated at folder application/build/libs/.

If we want to build a Docker image, we could execute the command below:

docker build -t johnniang/halo:project-structure .

# Test the Docker image
docker run -it --rm -p8090:8090 johnniang/halo:project-structure

Which issue(s) this PR fixes:

Fixes #2730

Special notes for your reviewer:

Does this PR introduce a user-facing change?

重构项目结构以支持发布插件所需的依赖。

[codecov]

Codecov Report

Merging #3552 (76cf602) into main (7ca5270) will decrease coverage by 1.98%.
The diff coverage is 58.73%.

@@             Coverage Diff              @@
##               main    #3552      +/-   ##
============================================
- Coverage     61.72%   59.75%   -1.98%     
+ Complexity     2572     2188     -384     
============================================
  Files           408      337      -71     
  Lines         12921    11273    -1648     
  Branches       1026      837     -189     
============================================
- Hits           7976     6736    -1240     
+ Misses         4458     4132     -326     
+ Partials        487      405      -82     

Impacted Files	Coverage Δ
...cation/src/main/java/run/halo/app/Application.java	20.00% <ø> (ø)
...run/halo/app/actuator/DatabaseInfoContributor.java	20.00% <ø> (ø)
...java/run/halo/app/actuator/GlobalInfoEndpoint.java	1.56% <ø> (ø)
...va/run/halo/app/config/ExtensionConfiguration.java	66.66% <ø> (ø)
...p/config/HaloAnonymousAuthenticationWebFilter.java	27.27% <ø> (ø)
...in/java/run/halo/app/config/HaloConfiguration.java	100.00% <ø> (ø)
...c/main/java/run/halo/app/config/SwaggerConfig.java	100.00% <ø> (ø)
...c/main/java/run/halo/app/config/WebFluxConfig.java	72.41% <ø> (ø)
...a/run/halo/app/config/WebServerSecurityConfig.java	94.11% <ø> (ø)
.../java/run/halo/app/console/ConsoleProxyFilter.java	0.00% <ø> (ø)
... and 174 more

... and 379 files with indirect coverage changes

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[guqing]

需要将下列 utils 放入 api 模块：

• run.halo.app.infra.utils.PathUtils
• run.halo.app.infra.utils.JsonUtils

还需要将 core/extension 下的那些 extension 放进来比如 Post、SinglePage、Comment 等，以及依赖到 infra 下的 ConditionList、ConditionStatus 等

还需要将下列类放进去

• run.halo.app.infra.ExternalUrlSupplier
• run.halo.app.infra.SystemSetting
• run.halo.app.infra.SystemVersionSupplier

[guqing]

api platform(project(':platform:application')) 貌似应该声明在 constraints 里面，否则在插件无法通过implementation platform('run.halo.tools.platform:plugin:2.4.0-SNAPSHOT')使用

Could not resolve: run.halo.tools.platform:plugin:2.4.0-SNAPSHOT

[guqing]

期望插件中可以引入一个依赖然后自动包含所有 halo 引入过的依赖 并且 scope 为 provide/compileOnly 这样插件可以直接使用且不会打包到插件中

[guqing]

/approve

[ruibaby]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: guqing, ruibaby

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• OWNERS [guqing,ruibaby]

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