Choose what files/folders will get restored

[grote]

When restoring backed up files, Seedvault currently only offers an all or nothing UI. We want to improve this, so users can choose which files they want to restore.

• [ ] New restore UI allowing selection of files/folders to restore before actual restore process starts
• [ ] Enable restore in normal UI, so users can restore files even after completing their device setup wizard. This needs to warn about overwriting existing files or creating duplicates