WIP: Remove the ForkedProjectLink model

What does this MR do?

This removes the deprecated ForkedProjectLink model.

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/38883

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides

	1 Message
	This merge request adds or changes files that require a review from the Database team.

Database Review

The following files require a review from the Database team:

• db/migrate/20180827133754_remove_forked_project_link.rb
• db/schema.rb

To make sure these changes are reviewed, take the following steps:

1. Edit your merge request, and add gl-database to the list of Group approvers.
2. Mention @gl-database in a separate comment, and explain what needs to be reviewed by the team. Please don't mention the team until your changes are ready for review.

Generated by Danger

closed