Align Strategy configuration and documentation

What does this MR do?

Align Strategy configuration and documentation.

Related issues

Closes #2149 (closed)

Testing

global:
  pages:
    enabled: true
gitlab:
  sidekiq:
    deployment:
      strategy:
        type: Recreate
  gitlab-pages:
    deployment:
      strategy:
        type: Recreate
registry:
  deployment:
    strategy:
      type: Recreate

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for omnibus-gitlab opened