WIP: Pinned Statuses

Changes

• add pinned timeline
• update user_profile.vue to show pinned timeline along with the user timeline
• pass timelineName down to the status component to make it possible to do extra styling ("📌 Pinned post") for the pinned timeline

Questions

• not sure how to show server errors so I just used alert() for now.
• also not sure how to localize server errors.

Screenshot

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I apologize for my editor which did some formatting I couldn't revert.