refactor(files_reminders): migrate app to Vue 3

[susnux]

• for 📦 ❗️Vue 3 Migration - NC33 Roadmap #55428

Summary

• migrate to Vue 3
• migrate to script-setup
• use consistent folder structure and script names
• added some unit tests

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[susnux]

/compile rebase