Show the preferences cog in reference previews:
- Cog wheel size/styling should match existing Page Previews (Discussed in T256504: Page previews cog should use OOUI settings icon)
- Logged-in users: Clicking should send users to the appearance preference tab where Reference Previews can be disabled, matching the behavior of Page Previews. The preferences will be merged into a joint preference, see T265709: Merge Page Preview and Reference Preview preferences
- Anonymous users: Clicking should open the merged Previews settings pop-up, edited/created in T265709: Merge Page Preview and Reference Preview preferences
- Hide cog wheel on RefPreviews popups on beta feature wikis
- Add settings to footer of reference previews analog to the settings solution in page previews.