Add maintainer role requirement version information to import docs

What does this MR do?

Add maintainer role requirement version information to import-related documentation.

GitHub import Rake task:

• Before: https://docs.gitlab.com/ee/administration/raketasks/github_import.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/administration/raketasks/github_import.html

Import API:

• Before: https://docs.gitlab.com/ee/api/import.html#import-repository-from-github
• After: https://main-ee-120057.docs.gitlab-review.app/ee/api/import.html#import-repository-from-github

Project import and export API:

• Before: https://docs.gitlab.com/ee/api/project_import_export.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/api/project_import_export.html#prerequisites

Version-specific upgrading instructions:

• Before: https://docs.gitlab.com/ee/update/index.html#version-specific-upgrading-instructions
• After: https://main-ee-120057.docs.gitlab-review.app/ee/update/index.html#version-specific-upgrading-instructions

Migrate groups by direct transfer (recommended):

• Before: https://docs.gitlab.com/ee/user/group/import/index.html#prerequisites
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/group/import/index.html#prerequisites

Import your project from Bitbucket Cloud to GitLab:

• Before: https://docs.gitlab.com/ee/user/project/import/bitbucket.html#prerequisites
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/bitbucket.html#prerequisites

Import your project from Bitbucket Server:

• Before: https://docs.gitlab.com/ee/user/project/import/bitbucket_server.html#import-your-bitbucket-repositories
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/bitbucket_server.html#prerequisites

FogBugz importer:

• Before: https://docs.gitlab.com/ee/user/project/import/fogbugz.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/fogbugz.html#prerequisites

Gitea importer:

• Before: https://docs.gitlab.com/ee/user/project/import/gitea.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/gitea.html#prerequisites

Import your project from GitHub to GitLab:

• Before: https://docs.gitlab.com/ee/user/project/import/github.html#prerequisites
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/github.html#prerequisites

Import and migrate projects:

• Before: https://docs.gitlab.com/ee/user/project/import/index.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/index.html

Import your Jira project issues to GitLab:

• Before: https://docs.gitlab.com/ee/user/project/import/jira.html#prerequisites
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/jira.html#prerequisites

Import multiple repositories by uploading a manifest file:

• Before: https://docs.gitlab.com/ee/user/project/import/manifest.html#requirements
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/manifest.html#prerequisites

Import project from repository by URL:

• Before: https://docs.gitlab.com/ee/user/project/import/repo_by_url.html
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/import/repo_by_url.html#prerequisites

Import a project and its data:

• Before: https://docs.gitlab.com/ee/user/project/settings/import_export.html#import-a-project-and-its-data
• After: https://main-ee-120057.docs.gitlab-review.app/ee/user/project/settings/import_export.html#import-a-project-and-its-data

Author's checklist

• Optional. Consider taking the GitLab Technical Writing Fundamentals course.
• Follow the:
  • Documentation process.
  • Documentation guidelines.
  • Style Guide.
• If you're adding or changing the main heading of the page (H1), ensure that the product tier badge is added.
• If you are a GitLab team member, request a review based on:
  • The documentation page's metadata.
  • The associated Technical Writer.

If you are a GitLab team member and only adding documentation, do not add any of the following labels:

• ~"frontend"
• ~"backend"
• ~"type::bug"
• ~"database"

These labels cause the MR to be added to code verification QA issues.

Reviewer's checklist

Documentation-related MRs should be reviewed by a Technical Writer for a non-blocking review, based on Documentation Guidelines and the Style Guide.

If you aren't sure which tech writer to ask, use roulette or ask in the #docs Slack channel.

• If the content requires it, ensure the information is reviewed by a subject matter expert.
• Technical writer review items:
  • Ensure docs metadata is present and up-to-date.
  • Ensure the appropriate labels are added to this MR.
  • Ensure a release milestone is set.
  • If relevant to this MR, ensure content topic type principles are in use, including:
    • The headings should be something you'd do a Google search for. Instead of Default behavior, say something like Default behavior when you close an issue.
    • The headings (other than the page title) should be active. Instead of Configuring GDK, say something like Configure GDK.
    • Any task steps should be written as a numbered list.
    • If the content still needs to be edited for topic types, you can create a follow-up issue with the docs-technical-debt label.
• Review by assigned maintainer, who can always request/require the reviews above. Maintainer's review can occur before or after a technical writer review.