Combine import, export, and subscribe options into dropdown

What does this MR do and why?

Moves export/import/subscribe buttons into a single dropdown

• Updates Edit and New label text I'm going to move this into a separate MR to keep this focused on the dropdown
• This merge request does not update the Select project to open... select/dropdown button

Screenshots or screen recordings

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MR acceptance checklist

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#398228 (closed)