Add state mover for gitlab_project_integration_external_wiki

Heidi Berryrequested to merge
state-mover-external-wiki-int into main

This change fixes a documentation error and implements automatic state migration for a GitLab integration resource that was renamed in version 19.0.

The main updates include:

  • Correcting the documentation to show the proper old name gitlab_integration_external_wiki instead of the incorrect gitlab_integration_external_wiki_resource
  • Adding code that automatically transfers user configuration data from the old resource name to the new one (gitlab_project_integration_external_wiki) when users upgrade
  • Including safety checks to ensure the migration only happens between the correct resource types and providers
  • Adding comprehensive tests to verify the migration works properly and requires Terraform version 1.8 or later

This allows users to smoothly upgrade their GitLab external wiki integrations without manually recreating their configurations, making the version upgrade process much easier.

Part of #6717

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