Move EE prepend and include calls to the end of models

What does this MR do?

This moves all instances of prepend EE::Something and include EE::Something in models to the last line of the corresponding model. This pushes EE specific code further down the files, reducing the likelihood of developers running into merge conflicts.

This only takes care of models, primarily to keep the size of the MRs at a size that can actually be reviewed.

Approach

This was done using the following Ruby script: https://gitlab.com/gitlab-org/release/framework/snippets/1773219

This MR depends on the changes introduced in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22987.

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/8241

Does this MR meet the acceptance criteria?

• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• EE specific content should be in the top level /ee folder