Add chunked transfer support for rendering templates

[JohnNiang]

What type of PR is this?

/kind improvement
/area core
/milestone 2.20.x

What this PR does / why we need it:

This PR adds chunked transfer support for rendering templates, which means that the max memory used by rendering template will be max chunk size instead of size of rendering result.

Users can define the max chunk size like below:

spring:
  thymeleaf:
    reactive:
      maxChunkSize: 8KB # Setting to 0 will disable the chunked response.

Special notes for your reviewer:

1. Try to start Halo instance

2. Execute the command like below and see if the response headers contain transfer-encoding: chunked:

   http http://localhost:8090/ -p h
   HTTP/1.1 200 OK
   Cache-Control: no-cache, no-store, max-age=0, must-revalidate
   Content-Language: en-CN
   Content-Type: text/html
   Expires: 0
   Pragma: no-cache
   Referrer-Policy: strict-origin-when-cross-origin
   Vary: Origin
   Vary: Access-Control-Request-Method
   Vary: Access-Control-Request-Headers
   X-Content-Type-Options: nosniff
   X-Frame-Options: SAMEORIGIN
   X-XSS-Protection: 0
   content-encoding: gzip
   set-cookie: XSRF-TOKEN=1e677724-ce82-4b63-911c-f78b22cd9169; Path=/
   transfer-encoding: chunked

Does this PR introduce a user-facing change?

优化模板渲染时所需的内存

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 88.23529% with 4 lines in your changes missing coverage. Please review.

Project coverage is 58.11%. Comparing base (6cd8dc8) to head (07d9758).
Report is 78 commits behind head on main.

Files with missing lines	Patch %	Lines
.../run/halo/app/theme/engine/HaloTemplateEngine.java	40.00%	3 Missing ⚠️
...main/java/run/halo/app/theme/HaloViewResolver.java	96.55%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6580      +/-   ##
============================================
- Coverage     58.18%   58.11%   -0.08%     
- Complexity     3774     3919     +145     
============================================
  Files           651      670      +19     
  Lines         22125    22990     +865     
  Branches       1538     1573      +35     
============================================
+ Hits          12873    13360     +487     
- Misses         8641     9012     +371     
- Partials        611      618       +7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ruibaby]

此 PR 会导致部分插件的功能失效，比如：

1. https://github.com/webp-sh/halo-plugin-webp-cloud
2. https://github.com/guqing/plugin-cloudinary

暂不确定是否有其他插件也有类似的问题。

[JohnNiang]

此 PR 会导致部分插件的功能失效，比如：

1. webp-sh/halo-plugin-webp-cloud
2. guqing/plugin-cloudinary

暂不确定是否有其他插件也有类似的问题。

失效的插件可以参考 halo-sigs/plugin-page-cache#10 来修复这个问题。另外，这两个需求建议通过 Thymeleaf 的扩展来实现。

[JohnNiang]

/ping @halo-dev/sig-halo

I have refactored plugin plugin-webp-cloud in webp-sh/halo-plugin-webp-cloud#15

[guqing]

/lgtm

[ruibaby]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: guqing

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [guqing]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment