chore: convert Wire Data Model project to use folders - WPB-15572

[caldrian]

WPB-15572 [iOS] Convert groups to folders

Issue

Fixes file locations, removes unused files, converts groups to folders in Wire Data Model.

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Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.