[kotlin-spring] Adding DocumentationProvider and SwaggerUI

[sjoblomj]

This is my Kotlin Spring implementation of @cachescrubber's excellent work in #11258 and #11531.

A user can now select a Documentation Provider (None, Source, Springfox, Springdoc), an Annotation Library (None, Swagger1, Swagger2) and whether to use Swagger UI.

Please note that this removes the swaggerAnnotations option that previously existed! Considering this, it is probably a good idea to include this PR in version 6.0.0 with breaking changes, if the PR is deemed to be useful and of sufficient quality.

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
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@cachescrubber @wing328 @jimschubert @dr4ke616 @karismann @Zomzog @andrewemery @4brunu @yutaka0m

[cachescrubber]

@sjoblomj Thanks for your effort - I'll try provide more detailed feedback in the next days.

[wing328]

LGTM. Thanks for the PR 👍

[wing328]

@cachescrubber oops... sorry didn't see your comment earlier. Let us know your feedback and we'll file separate PRs instead 🙏

[cachescrubber]

No problem. Just skimmed over the changes - LGTM too. @sjoblomj - if you like please upgrade the Spring Boot version used in the generated poms / build.gradle files? They are still 2.2.0M3.

And the following REQ does apply to the spring kotlind generator too: #12220.

[sjoblomj]

No problem. Just skimmed over the changes - LGTM too. @sjoblomj - if you like please upgrade the Spring Boot version used in the generated poms / build.gradle files? They are still 2.2.0M3.

And the following REQ does apply to the spring kotlind generator too: #12220.

I've made a PR to update dependencies here: #12281

I'll take a look at #12220 and try to make a separate PR for it when I have time 👍

[ghost]

The problem described in #12220 is addressed in #12377.

[sdewinter-maqqie]

Since you have used hardcoded the content type as schema in for example apiInterface.mustache. It is not possible to generate content schemas for arrays.

This also is/was an issue in the java-spring and seems like #13332 is an bug report for this.