feat(Topics): Topics localization MVC-1 -> Enable Field Level Localization on topics & ship localized versions of /topics/devops/

What is changing in this MR?

Refactor of the Topics service methods in order to couple it with a field-level localization approach, below are the key items of this refactor:

• New Topics specific content types were created to fully support a proper field-level localization, these content types are as simple as possible in terms of fields number:
  • Topic Button

    
  • Topic Card

    
  • Topic External Video

    
  • Topic Header and Text

    
• Added the seoTitle and seoDescription to the Topics Content Type to avoid creating an specific SEO content type for Topics
• The code was refactored to work with both old content types and new content types causing no regressions when merged
• MVC-1 Refactoring to reduce code duplication and use Typescript
• Migration script implemented to migrate entry-level entries to field-level entries, the migration did run successfully with the Topics Devops Entry

Page with field-level localization migrated components

Production	Review app
https://about.gitlab.com/topics/devops	/topics/devops

Some other pages not migrated that should work the same

Production	Review app
https://about.gitlab.com/topics/devops/build-a-devops-team/	/topics/devops/build-a-devops-team/
https://about.gitlab.com/topics/gitops/	/topics/gitops/
https://about.gitlab.com/topics/agile-delivery/	/topics/agile-delivery/
https://about.gitlab.com/topics/ci-cd/continuous-integration-best-practices/	/topics/ci-cd/continuous-integration-best-practices/
https://about.gitlab.com/topics/devsecops/	/topics/devsecops/
https://about.gitlab.com/topics/version-control/	/topics/version-control/

Deploy steps

1. Publish the Topics DevOps field-level localization release
2. Merge this MR

Build Variables:

• Use Contentful Preview API

Related to #3728